If RESUME is cleared too soon, OPT HS A 6.8 tests will fail.

This patch removes the check for RESUME bit before SUSPEND
is set, and makes virthub sleep until RESUME has been held
for 20 ms. Additionally virthub waits after clearing RESUME
to allow musb to start generating SOFs before RESET.
Signed-off-by: Tony Lindgren <tony@atomide.com>