fix(rmm): fix static_checks warnings and errors

Fixes static_checks warning and errors listed below:

- docs/about/change-log.rst:52:
WARNING: Possible repeated word: 'the'
- lib/attestation/include/attestation_token.h:116:
WARNING: please, no space before tabs
- lib/attestation/include/attestation_token.h:118:
WARNING: please, no space before tabs
- lib/attestation/src/attestation_rnd.c:58:
WARNING: please, no spaces at the start of a line
- lib/attestation/src/attestation_rnd.c:59:
WARNING: please, no spaces at the start of a line
- lib/measurement/src/measurement.c:18:
WARNING: Missing a blank line after declarations
- lib/realm/src/buffer.c:231:
WARNING: externs should be avoided in .c and .cpp files
- lib/xlat/src/xlat_tables_core.c:128:
WARNING: else is not generally useful after a break or return
- plat/host/host_test/src/test_helpers.c:22:
WARNING: externs should be avoided in .c and .cpp files
- runtime/rmi/run.c:222:
WARNING: break is not useful after a goto
- runtime/rmi/run.c:228:
WARNING: break is not useful after a goto
- runtime/rsi/realm_attest.c:309:
WARNING: Missing a blank line after declarations
-plat/fvp/src/include/fvp_dram.h:
ERROR: includes not in order. Include order should be rmm_el3_ifc.h,
stddef.h, stdint.h

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: I46a7ad1216eae826b5adb9487b397f2ed783d932
diff --git a/lib/realm/src/include/buffer_private.h b/lib/realm/src/include/buffer_private.h
index 77b1a2a..cf0bb1c 100644
--- a/lib/realm/src/include/buffer_private.h
+++ b/lib/realm/src/include/buffer_private.h
@@ -21,3 +21,5 @@
 
 struct xlat_llt_info *get_cached_llt_info(void);
 uintptr_t slot_to_va(enum buffer_slot slot);
+bool memcpy_ns_read(void *dest, const void *ns_src, size_t size);
+bool memcpy_ns_write(void *ns_dest, const void *src, size_t size);