lib/bootmem: Prepare for OpenSBI

Add a new bootmem memory type OpenSBI.
It's similar to BL31 on aarch64.

Required for OpenSBI integration.

Change-Id: I5ceafd5a295f4284e99e12f7ea2aa4c6d1dbb188
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34140
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/include/program_loading.h

@@ -38,6 +38,7 @@ enum prog_type {
 	PROG_BL31,
 	PROG_BL32,
 	PROG_POSTCAR,
+	PROG_OPENSBI,
 };
 
 /*