AArch32: Add assembly helpers

This patch adds various assembly helpers for AArch32 like :

* cache management : Functions to flush, invalidate and clean
cache by MVA. Also helpers to do cache operations by set-way
are also added.

* stack management: Macros to declare stack and get the current
stack corresponding to current CPU.

* Misc: Macros to access co processor registers in AArch32,
macros to define functions in assembly, assert macros, generic
`do_panic()` implementation and function to zero block of memory.

Change-Id: I7b78ca3f922c0eda39beb9786b7150e9193425be
diff --git a/include/common/aarch32/assert_macros.S b/include/common/aarch32/assert_macros.S
new file mode 100644
index 0000000..f35fc6a
--- /dev/null
+++ b/include/common/aarch32/assert_macros.S
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef __ASSERT_MACROS_S__
+#define __ASSERT_MACROS_S__
+
+	/*
+	 * Assembler macro to enable asm_assert. We assume that the stack is
+	 * initialized prior to invoking this macro.
+	 */
+#define ASM_ASSERT(_cc) \
+.ifndef .L_assert_filename ;\
+	.pushsection .rodata.str1.1, "aS" ;\
+	.L_assert_filename: ;\
+			.string	__FILE__ ;\
+	.popsection ;\
+.endif ;\
+	b##_cc	300f ;\
+	ldr	r0, =.L_assert_filename ;\
+	mov	r1, #__LINE__ ;\
+	b	. ;\
+300:
+
+#endif /* __ASSERT_MACROS_S__ */