mmc: sh_mmcif: remove redundant initialization of 'opc'

Variable opc is initialized with a value that is never read, opc
is later re-assigned a newer value, hence the initialization can
be removed.

Cleans up clang warning:
drivers/mmc/host/sh_mmcif.c:919:6: warning: Value stored to 'opc'
during its initialization is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sh_mmcif.c

@@ -916,7 +916,7 @@ static void sh_mmcif_start_cmd(struct sh_mmcif_host *host,
 			       struct mmc_request *mrq)
 {
 	struct mmc_command *cmd = mrq->cmd;
-	u32 opc = cmd->opcode;
+	u32 opc;
 	u32 mask = 0;
 	unsigned long flags;