refactor(spm_mm): reorganize secure partition manager code

In preparation for adding the EL3 SPMC configuration as defined in
the FF-A specification, restructure the existing SPM_MM code.

With this restructuring of the code, the 'spm_mm' directory is
renamed as 'spm' and the code inside has been split into two
sub-directories named 'common' and 'spm_mm'. The code in 'spm_mm'
directory contains the code that implements the MM interface.
In subsequent patches, the 'spmc' directory will be introduced
under the 'spm' directory providing the code that implements
the 'FF-A' interface.

Currently the common functionality for S-EL1 partitions is
limited to assembler functions to enter and exit an SP
synchronously.

Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Change-Id: I37739b9b53bc68e151ab5c1c0c6a15b3ee362241
diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index 25c7964..7d83e3c 100644
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -18,7 +18,8 @@
     $(error EL3_EXCEPTION_HANDLING must be 1 for SPM-MM support)
   else
     $(info Including SPM Management Mode (MM) makefile)
-    include services/std_svc/spm_mm/spm_mm.mk
+    include services/std_svc/spm/common/spm.mk
+    include services/std_svc/spm/spm_mm/spm_mm.mk
   endif
 endif
 
@@ -40,6 +41,7 @@
 				services/std_svc/std_svc_setup.c		\
 				${PSCI_LIB_SOURCES}				\
 				${SPMD_SOURCES}					\
+				${SPM_MM_SOURCES}				\
 				${SPM_SOURCES}
 
 ifeq (${DISABLE_MTPMU},1)