USB: ohci-pxa27x: Allow NOCP and OCPM to be cleared

Some ohci-pxa27x platforms may require OCPM and NOCP in UHCRHDA to be
clear, but the existing code was only allowing setting.  This patch
ensures that these bits are clear if the respective flags are not set.
This is particularly important for the PXA3xx family where the
documentation says OCPM must be cleared, but it is set after reset.

Signed-off-by: Aric Blumer <aric@sdgsystems.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>