USB: dwc3: msm: Host: Don't turn off core clock when SS session is active

On 8974 V2 platform, core clock should not be turned off during
host bus suspend due to hardware bug when superspeed session is
active. Hence don't turn off master core clock during host bus
suspend when SS sesion is active.

Change-Id: I6d595e587bfaf4c3ac82a32922b03daaa0cd3fd7
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>