mmc: core: Silence compiler warning in __mmc_switch

Signed-off-by: Ulf Hansson <[e-mail]>
Signed-off-by: Chris Ball <[e-mail]>

drivers/mmc/core/mmc_ops.c

···
 	int err;
 	struct mmc_command cmd = {0};
 	unsigned long timeout;
-	u32 status;
+	u32 status = 0;
 	bool ignore_crc = false;
 
 	BUG_ON(!card);