Leave GPIO[7:6] pullups enabled

GPIO7 and GPIO6 are configured as default wake-up sources for
tusb6010.

without this patch MUSB is not able to enumerate
any device that draw power from it.

After applying this patch, we're passing in almost
all OTG Electrical Tests.

Signed-off-by: Felipe Balbi <felipe.lima@indt.org.br>
Signed-off-by: Tony Lindgren <tony@atomide.com>