amd/common/block/pi: Make agesa_heap_base() static

Convert agesa_heap_base() to static since it's unused outside of
heapmanager.c.

Change-Id: I3ee162985ca1ea36461ea413416d98451a700f8c
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/25457
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Richard Spiegel <richard.spiegel@silverbackltd.com>

src/soc/amd/common/block/include/amdblocks/agesawrapper.h

@@ -63,6 +63,4 @@ void SetNbEnvParams(GNB_ENV_CONFIGURATION *params);
 void SetFchMidParams(FCH_INTERFACE *params);
 void SetNbMidParams(GNB_MID_CONFIGURATION *params);
 
-void *agesa_heap_base(void);
-
 #endif /* __AGESAWRAPPER_H__ */

src/soc/amd/common/block/pi/heapmanager.c

@@ -19,7 +19,7 @@
 #include <cbmem.h>
 #include <string.h>
 
-void *agesa_heap_base(void)
+static void *agesa_heap_base(void)
 {
 	return cbmem_add(CBMEM_ID_RESUME_SCRATCH, BIOS_HEAP_SIZE);
 }