staging: mt7621-mmc: Fix ret.cooci warnings

Return the value directly instead of storing it in local variable err.
Remove the unused local variable err.
The semantic patch that fixes the first part of the problem is as follows

// <smpl>
@@
local idexpression ret;
expression e;
@@

-ret =
+return
     e;
-return ret;
// </smpl>
Signed-off-by: Bhanusree Pola <bhanusreemahesh@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-mmc/sd.c

@@ -752,7 +752,6 @@ static int msdc_app_cmd(struct mmc_host *mmc, struct msdc_host *host)
 {
 	struct mmc_command cmd;
 	struct mmc_request mrq;
-	u32 err;
 
 	memset(&cmd, 0, sizeof(struct mmc_command));
 	cmd.opcode = MMC_APP_CMD;
@@ -763,8 +762,7 @@ static int msdc_app_cmd(struct mmc_host *mmc, struct msdc_host *host)
 	mrq.cmd = &cmd; cmd.mrq = &mrq;
 	cmd.data = NULL;
 
-	err = msdc_do_command(host, &cmd, 0, CMD_TIMEOUT);
-	return err;
+	return msdc_do_command(host, &cmd, 0, CMD_TIMEOUT);
 }
 
 static int msdc_tune_cmdrsp(struct msdc_host *host, struct mmc_command *cmd)