Remove dependency between SPM_MM and ENABLE_SPM build flags

There are two different implementations of Secure Partition
management in TF-A. One is based on the "Management Mode" (MM)
design, the other is based on the Secure Partition Client Interface
(SPCI) specification. Currently there is a dependency between their
build flags that shouldn't exist, making further development
harder than it should be. This patch removes that
dependency, making the two flags function independently.

Before: ENABLE_SPM=1 is required for using either implementation.
        By default, the SPCI-based implementation is enabled and
        this is overridden if SPM_MM=1.

After: ENABLE_SPM=1 enables the SPCI-based implementation.
       SPM_MM=1 enables the MM-based implementation.
       The two build flags are mutually exclusive.

Note that the name of the ENABLE_SPM flag remains a bit
ambiguous - this will be improved in a subsequent patch. For this
patch the intention was to leave the name as-is so that it is
easier to track the changes that were made.

Change-Id: I8e64ee545d811c7000f27e8dc8ebb977d670608a
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/plat/arm/board/fvp/fvp_common.c b/plat/arm/board/fvp/fvp_common.c
index a948796..fca4d01 100644
--- a/plat/arm/board/fvp/fvp_common.c
+++ b/plat/arm/board/fvp/fvp_common.c
@@ -96,10 +96,10 @@
 	ARM_MAP_BL1_RW,
 #endif
 #endif /* TRUSTED_BOARD_BOOT */
-#if ENABLE_SPM && SPM_MM
+#if SPM_MM
 	ARM_SP_IMAGE_MMAP,
 #endif
-#if ENABLE_SPM && !SPM_MM
+#if ENABLE_SPM
 	PLAT_MAP_SP_PACKAGE_MEM_RW,
 #endif
 #if ARM_BL31_IN_DRAM
@@ -127,16 +127,16 @@
 	MAP_DEVICE0,
 	MAP_DEVICE1,
 	ARM_V2M_MAP_MEM_PROTECT,
-#if ENABLE_SPM && SPM_MM
+#if SPM_MM
 	ARM_SPM_BUF_EL3_MMAP,
 #endif
-#if ENABLE_SPM && !SPM_MM
+#if ENABLE_SPM
 	PLAT_MAP_SP_PACKAGE_MEM_RO,
 #endif
 	{0}
 };
 
-#if ENABLE_SPM && defined(IMAGE_BL31) && SPM_MM
+#if defined(IMAGE_BL31) && SPM_MM
 const mmap_region_t plat_arm_secure_partition_mmap[] = {
 	V2M_MAP_IOFPGA_EL0, /* for the UART */
 	MAP_REGION_FLAT(DEVICE0_BASE,				\
@@ -190,7 +190,7 @@
 }
 #endif
 
-#if ENABLE_SPM && defined(IMAGE_BL31) && SPM_MM
+#if defined(IMAGE_BL31) && SPM_MM
 /*
  * Boot information passed to a secure partition during initialisation. Linear
  * indices in MP information will be filled at runtime.