usb: phy: Remove flags for clock enable/disable

This change removes flags to enable/disable clocks
from phy driver so that clocks framework can take care
of ref count for enabling/disabling clocks. This change
also fixes the check if phy is already suspended or not.

Change-Id: I5073b02d1e1af53ed56d363763cde3177028cf4e
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>