ARM: dts: bcm2835-rpi-zero-w: Drop unnecessary pinctrl

There is no need to specify a pinctrl for the reset GPIO. So we better
remove this avoid a potential conflict between pinctrl and pwrseq
after the pinmux driver has been changed to strict:

pinctrl-bcm2835 20200000.gpio: pin gpio41 already requested by wifi-pwrseq;
cannot claim for pinctrl-bcm2835:499
pinctrl-bcm2835 20200000.gpio: pin-41 (pinctrl-bcm2835:499) status -22
pwrseq_simple: probe of wifi-pwrseq failed with error -22

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>