pinctrl-bcm2835: Fix cut-and-paste error in "pull" parsing

The DT bindings for pinctrl-bcm2835 allow both the function and pull
to contain either one entry or one per pin. However, an error in the
DT parsing can cause failures if the number of pulls differs from the
number of functions.

Cc: stable@vger.kernel.org
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Reviewed-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>