Remove build option `ASM_ASSERTION`

The build option `ENABLE_ASSERTIONS` should be used instead. That way
both C and ASM assertions can be enabled or disabled together.

All occurrences of `ASM_ASSERTION` in common code and ARM platforms have
been replaced by `ENABLE_ASSERTIONS`.

ASM_ASSERTION has been removed from the user guide.

Change-Id: I51f1991f11b9b7ff83e787c9a3270c274748ec6f
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/lib/aarch64/misc_helpers.S b/lib/aarch64/misc_helpers.S
index 84265e0..74550aa 100644
--- a/lib/aarch64/misc_helpers.S
+++ b/lib/aarch64/misc_helpers.S
@@ -215,7 +215,7 @@
 	tmp1         .req x4
 	tmp2         .req x5
 
-#if ASM_ASSERTION
+#if ENABLE_ASSERTIONS
 	/*
 	 * Check for M bit (MMU enabled) of the current SCTLR_EL(1|3)
 	 * register value and panic if the MMU is disabled.
@@ -228,7 +228,7 @@
 
 	tst	tmp1, #SCTLR_M_BIT
 	ASM_ASSERT(ne)
-#endif /* ASM_ASSERTION */
+#endif /* ENABLE_ASSERTIONS */
 
 	/* stop_address is the address past the last to zero */
 	add	stop_address, cursor, length
@@ -247,7 +247,7 @@
 	mov	tmp2, #(1 << 2)
 	lsl	block_size, tmp2, block_size
 
-#if ASM_ASSERTION
+#if ENABLE_ASSERTIONS
 	/*
 	 * Assumes block size is at least 16 bytes to avoid manual realignment
 	 * of the cursor at the end of the DCZVA loop.
@@ -444,7 +444,7 @@
  * --------------------------------------------------------------------------
  */
 func memcpy16
-#if ASM_ASSERTION
+#if ENABLE_ASSERTIONS
 	orr	x3, x0, x1
 	tst	x3, #0xf
 	ASM_ASSERT(eq)