ARM: dts: imx53-qsb: Let the codec control MCLK pinctrl
The hog pinctrl hog is meant for pins that do not have an
associated driver.
The MX53_PAD_GPIO_0__CCM_SSI_EXT1_CLK pin is the one that
provides the MCLK signal to the SGTL5000 codec, so a
better represenation is to move it under the codec node.
While at it, change the pinctrl value from 0x80000000 to the
POR reset value of register IOMUXC_SW_PAD_CTL_PAD_GPIO_0.