diag: Do not prevent HSIC suspend in special cases

Diag driver prevents HSIC from suspending if it is in Memory Device
Mode. Make changes to remove this condition and allow suspend in
all logging modes.

Change-Id: Ia1f43b881f1ea247ba17e067d6ac1a1da021ad9e
Signed-off-by: Ravi Aravamudhan <aravamud@codeaurora.org>