pinctrl: bcm2835: Add support for BCM2711 pull-up functionality

commit e38a9a43 upstream.

The BCM2711 has a new way of selecting the pull-up/pull-down setting
for a GPIO pin. The registers used for the BCM2835, GP_PUD and
GP_PUDCLKn0, are no longer connected. A new set of registers,
GP_GPIO_PUP_PDN_CNTRL_REGx must be used. This commit will add
a new compatible string "brcm,bcm2711-gpio" and the kernel
driver will use it to select which method is used to select
pull-up/pull-down.

This patch based on a patch by Al Cooper which was intended for the
BCM7211. This is a bugfixed and improved version.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Eric Anholt <eric@anholt.net>