lib/bootmem: allow architecture specific bootmem ranges

A architecture-specific function, named bootmem_arch_add_ranges(),
is added so that each architecture can add entries into the bootmem
memory map. This allows for a common write_tables() implementation
to avoid code duplication.

Change-Id: I834c82eae212869cad8bb02c7abcd9254d120735
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/14434
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/lib/bootmem.c

@@ -39,6 +39,8 @@ void bootmem_init(void)
 
 	/* Add memory used by CBMEM. */
 	cbmem_add_bootmem();
+
+	bootmem_arch_add_ranges();
 }
 
 void bootmem_add_range(uint64_t start, uint64_t size, uint32_t type)