mmc: sdhci-msm: Reenable cd gpio on system resume

In 3.18 kernel mmc_gpiod_request_cd_irq() is not called as part of
call to mmc_gpio_request_cd(). During probe this is taken care of
by calling mmc_gpiod_request_cd_irq() from mmc_start_host(), but if
mmc_gpio_request_cd() followed by a mmc_gpio_free_cd() is invoked
after mmc_start_host() (such as in system suspend/resume path) then
mmc_gpiod_request_cd_irq() needs to be called explicitly.

Instead of free/request the card detect irq, just disable/enable
the irq in system suspend/resume path.

CRs-fixed: 876453
Change-Id: I976cd5061c2a7d8321e48ee23a44acfd552a37fc
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>