build: always prefix section names with `.`

Some of our specialized sections are not prefixed with the conventional
period. The compiler uses input section names to derive certain other
section names (e.g. `.rela.text`, `.relacpu_ops`), and these can be
difficult to select in linker scripts when there is a lack of a
delimiter.

This change introduces the period prefix to all specialized section
names.

BREAKING-CHANGE: All input and output linker section names have been
 prefixed with the period character, e.g. `cpu_ops` -> `.cpu_ops`.

Change-Id: I51c13c5266d5975fbd944ef4961328e72f82fc1c
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/plat/arm/common/aarch64/arm_helpers.S b/plat/arm/common/aarch64/arm_helpers.S
index b470781..ed85ea1 100644
--- a/plat/arm/common/aarch64/arm_helpers.S
+++ b/plat/arm/common/aarch64/arm_helpers.S
@@ -129,7 +129,7 @@
 	 * Single cpu stack in coherent memory.
 	 * ----------------------------------------------------
 	 */
-declare_stack platform_coherent_stacks, tzfw_coherent_mem, \
+declare_stack platform_coherent_stacks, .tzfw_coherent_mem, \
 		PLATFORM_STACK_SIZE, 1, CACHE_WRITEBACK_GRANULE
 
 #endif	/* defined(IMAGE_BL1) || defined(IMAGE_BL2) */