mmc: core: Use new flag for suspending clk scaling

Currently we disable clk scaling when card goes to suspend. This can
cause issue when we want to change the devfreq governor. Mmc devfreq
handler will ignore requests coming from devfreq framework,
causing unexpected behaviours.

Add a new flag for suspending clk scaling so that, any devfreq
request which comes while mmc is suspended will get queued and
then serviced as part of deferred scaling.

Change-Id: I640299724ece3390652abcec7eb3da3382f63f8a
Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
Signed-off-by: Ram Prakash Gupta <rampraka@codeaurora.org>