[U-Boot] [PATCH] mmc: cat u8 to u64 to avoid unexpected error

[Haibo Chen <haibo.chen@nxp.com>]

Suspicious implicit sign extension exist. ext_csd[] is defined
as "u8", capacity is defined as u64, so u8 is promoted to signed
int first int the "|" expersion, then the sign extended to u64.
if the tmp sign value is largeer than 0x7fffffff, after the sign
extension, the upper bits of the result will all be 1.
Thanks to coverity <http://www.coverity.com>

e.g.
	u8  data_8;
	u64 data_64;

	data_8 = 0x80;
	data_64 = data_8 << 24; //0xffffffff80000000
	data_64 = ((u64)data_8) << 24;  //0x80000000

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
---
 drivers/mmc/mmc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 43ea0bb..c1d1dc6 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1176,10 +1176,10 @@ static int mmc_startup(struct mmc *mmc)
 			 * ext_csd's capacity is valid if the value is more
 			 * than 2GB
 			 */
-			capacity = ext_csd[EXT_CSD_SEC_CNT] << 0
-					| ext_csd[EXT_CSD_SEC_CNT + 1] << 8
-					| ext_csd[EXT_CSD_SEC_CNT + 2] << 16
-					| ext_csd[EXT_CSD_SEC_CNT + 3] << 24;
+			capacity = ((u64)ext_csd[EXT_CSD_SEC_CNT]) << 0
+					| ((u64)ext_csd[EXT_CSD_SEC_CNT + 1]) << 8
+					| ((u64)ext_csd[EXT_CSD_SEC_CNT + 2]) << 16
+					| ((u64)ext_csd[EXT_CSD_SEC_CNT + 3]) << 24;
 			capacity *= MMC_MAX_BLOCK_LEN;
 			if ((capacity >> 20) > 2 * 1024)
 				mmc->capacity_user = capacity;
-- 
1.9.1