mmc: sdhci-msm: Do not disable card detect IRQ on system suspend

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.
So, in msm-3.18, change 4073b350d
('mmc: sdhci-msm: Reenable cd gpio on system resume') disable/enable
the irq in system suspend/resume path. This change has been kept since
then. However, since mmc_gpio_free_cd() is obsoleted from 4.4 kernel,
this change is not needed anymore. So, remove the codes introduced from
this change.

Change-Id: I113cbae8494626c7385113017b11a2fdf6de0f98
Signed-off-by: Can Guo <cang@codeaurora.org>