uboot-imx

imx: iomux: fix snvs usage for i.MX6ULL

SNVS TAMPER pin and BOOT MODE pins are in SNVS IOMUXC module,
not in IOMUXC, so correct the related registers' offset.

Use IOMUX_CONFIG_LPSR flag for these pins, so we can differentiate
them from iomuxc pins.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: "Benoît Thébaudeau" <benoit.thebaudeau.dev@gmail.com>