spl: spl_mmc.c Correct blk_dread() return value check

The function blk_dread will return -ENOSYS on failure or on success the
number of blocks read, which must be the number asked to read (otherwise
it failed somewhere).  Correct this check.
Signed-off-by: NTom Rini <trini@konsulko.com>

common/spl/spl_mmc.c

@@ -200,7 +200,7 @@ static int mmc_load_image_raw_os(struct spl_image_info *spl_image,
 		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
 		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS,
 		(void *) CONFIG_SYS_SPL_ARGS_ADDR);
-	if (count == 0) {
+	if (count != CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS) {
 #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
 		puts("mmc_load_image_raw_os: mmc block read error\n");
 #endif