ARM: bcm: Enable PINCTRL for ARCH_BRCMSTB

ARCH_BRCMSTB needs to use the BCM2835 pin controller for chips like
BCM7211 which adopted that pin controller for GPIO.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>