mmc: core: Init mmc host clock scaling suspend state

We track the mmc clock scaling state using mmc host's flag is_suspended.
During the first SD card removal event, the mmc driver suspends the clock
scaling to cancel any pending scaling work; however, the is_suspended flag
value remains set to TRUE. When the SD card is inserted and removed again,
the mmc shall not suspend the clock scaling because the is_suspended flag
is set to TRUE.
Resetting the mmc host clock scaling's is_suspended to FALSE during the
clock scaling initialization to ensure that the driver suspend the clock
scaling properly for subsequent card removal events.

Change-Id: If8bc6c3f4a545900dd1d783d2cfdf2bfd164073d
Signed-off-by: Can Guo <cang@codeaurora.org>