drivers: gpio: imx rt11xx: fix wrong gpio pull disable mask

Fixes: #75390
A wrong bit mask (wrong: IOMUXC_SW_PAD_CTL_PAD_PUS_MASK = 0x8) was used.
That bit mask is for PUE/PUS-type gpio registers, but this is the
section for registers with alternative PULL (PDRV) type layout.
Right bit mask: IOMUXC_SW_PAD_CTL_PAD_PULL_MASK

Signed-off-by: Nils Larsen <nils.larsen@posteo.de>