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/include/common/runtime_svc.h b/include/common/runtime_svc.h
index 472a32a..4793e2f 100644
--- a/include/common/runtime_svc.h
+++ b/include/common/runtime_svc.h
@@ -72,7 +72,7 @@
  */
 #define DECLARE_RT_SVC(_name, _start, _end, _type, _setup, _smch)	\
 	static const rt_svc_desc_t __svc_desc_ ## _name			\
-		__section("rt_svc_descs") __used = {			\
+		__section(".rt_svc_descs") __used = {			\
 			.start_oen = (_start),				\
 			.end_oen = (_end),				\
 			.call_type = (_type),				\