devfreq: allow switching governor when device suspended

When device is suspended, switching governor is not
allowed, governor code is updated to handle this scenario.

Allow governor switch when device is in suspended state.

Change-Id: I03609ee9f3cef3ddc0d8a640e07d20e2003cece0
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>