spl: spl_mmc: Disambiguate error message

The error message "spl: mmc block read error" may come from two
different functions, so we should better annotate the function name
where the error comes from to help debugging.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

common/spl/spl_mmc.c

@@ -83,7 +83,7 @@ static int mmc_load_image_raw_sector(struct mmc *mmc, unsigned long sector)
 end:
 	if (ret) {
 #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
-		puts("spl: mmc block read error\n");
+		puts("mmc_load_image_raw_sector: mmc block read error\n");
 #endif
 		return -1;
 	}
@@ -186,7 +186,7 @@ static int mmc_load_image_raw_os(struct mmc *mmc)
 		(void *) CONFIG_SYS_SPL_ARGS_ADDR);
 	if (count == 0) {
 #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
-		puts("spl: mmc block read error\n");
+		puts("mmc_load_image_raw_os: mmc block read error\n");
 #endif
 		return -1;
 	}