tree: Drop unused <cbmem.h>

Change-Id: If8be8dc26f2729f55dc6716e6d01e2b801d79e44
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81829
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <ericllai@google.com>

src/arch/riscv/payload.c

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
-#include <cbmem.h>
 #include <program_loading.h>
 #include <stdint.h>
 #include <arch/boot.h>