arm64: dts: ti: k3-am68-sk-base-board: Add clklb pin mux for mmc1

arm64: dts: ti: k3-am68-sk-base-board: Add clklb pin mux for mmc1

mmc1 is not functional and needs clock loopback so that it can
create sampling clock from this for high speed SDIO operations.
Thus, add clklb pin mux to get mmc1 working.

Fixes: a266c180b398 ("arm64: dts: ti: k3-am68-sk: Add support for AM68 SK base board")
Signed-off-by: Bhavya Kapoor <b-kapoor@ti.com>
Reviewed-by: Neha Malcom Francis <n-francis@ti.com>
Reviewed-by: Manorit Chawdhry <m-chawdhry@ti.com>
Link: https://lore.kernel.org/r/20240809072231.2931206-1-b-kapoor@ti.com
Signed-off-by: Nishanth Menon <nm@ti.com>