Whenever Suspend PHY bit is set on AM437x devices,
USB will not work due to Set EP Configuration command
always failing.

This was only found after a recent commit 2164a476 (usb:
dwc3: set SUSPHY bit for all cores, which will be merged
for v3.19) added a missing *required* step to dwc3
initialization. Synopsys Databook requires that we enable
Suspend PHY bit after initialization but that, unfortunately,
breaks AM437x.
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>