lib/cbmem: remove cbmem_region_used()

The cbmem_region_used() function wasn't being utilized outside this
module. Threfore, reduce the surface area.

Change-Id: I28a9d02221048ab0aa4cd3d986d17ee7692ce636
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/20858
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Sumeet R Pawnikar <sumeet.r.pawnikar@intel.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/include/cbmem.h

@@ -97,8 +97,6 @@ int cbmem_recovery(int s3resume);
 void *cbmem_add(u32 id, u64 size);
 /* Find a cbmem entry of a given id. These return NULL on failure. */
 void *cbmem_find(u32 id);
-/* Get location and size of CBMEM region in memory */
-void cbmem_region_used(uintptr_t *base, size_t *size);
 
 /* Indicate to each hook if cbmem is being recovered or not. */
 typedef void (* const cbmem_init_hook_t)(int is_recovery);