spm-mm: fix MISRA C-2012 Rule 2.3 spm_mm_boot_info_t defined but never used.

Following merge of patchset [1] the spm_mm_boot_info_t structure is
included in few platform files unconditionally even when SPM_MM option
is disabled.

[1] https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/2647

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I68bc034c9348b5d9bcfd2e5217b781df5ad1b369
diff --git a/plat/arm/board/tc0/tc0_plat.c b/plat/arm/board/tc0/tc0_plat.c
index b1ec39b..0546192 100644
--- a/plat/arm/board/tc0/tc0_plat.c
+++ b/plat/arm/board/tc0/tc0_plat.c
@@ -15,7 +15,10 @@
 #include <plat/arm/common/plat_arm.h>
 #include <plat/common/platform.h>
 #include <drivers/arm/sbsa.h>
+
+#if SPM_MM
 #include <services/spm_mm_partition.h>
+#endif
 
 /*
  * Table of regions for different BL stages to map using the MMU.