mmc: sdhci-pci: fix simple_return.cocci warnings

drivers/mmc/host/sdhci-pci-core.c:447:1-4: WARNING: end returns can be simpified

 Simplify a trivial if-return sequence.  Possibly combine with a
 preceding function call.

Generated by: scripts/coccinelle/misc/simple_return.cocci

CC: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>