cbmem_top_chipset: Change the return value to uintptr_t

Get rid of a lot of casts.

Change-Id: I93645ef5dd270905ce421e68e342aff4c331eae6
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69078
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jakub Czapiga <jacz@semihalf.com>
diff --git a/src/lib/imd_cbmem.c b/src/lib/imd_cbmem.c
index a855cf1..91c8621 100644
--- a/src/lib/imd_cbmem.c
+++ b/src/lib/imd_cbmem.c
@@ -18,11 +18,11 @@
 void *cbmem_top(void)
 {
 	if (ENV_CREATES_CBMEM) {
-		static void *top;
+		static uintptr_t top;
 		if (top)
-			return top;
+			return (void *)top;
 		top = cbmem_top_chipset();
-		return top;
+		return (void *)top;
 	}
 	if (ENV_POSTCAR || ENV_RAMSTAGE)
 		return (void *)_cbmem_top_ptr;