mmc: sdhci: clean up command error handling

Avoid multiple tests while handling a command error; simplify the code.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
[ Goes with "mmc: sdhci: fix command response CRC error handling" ]
Cc: stable@vger.kernel.org # v4.5+
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>