ARM: dts: dra7xx/am57xx: remove muxing for MMC/SD card detect pin

MMC1 uses GPIO for card detect and the muxing for card detect
pin does not change for the various MMC/SD modes.

Muxing for card detect pin should be in U-Boot along
with all other non-special-cased pins. Remove muxing for MMC/SD
card detect pin here.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>