mmc: renesas-sdhi: Add compatible string for rzg2l-sdhi

mmc: renesas-sdhi: Add compatible string for rzg2l-sdhi

After the recent dts/upstream subtree merge, the sdhi compatible string
used in the device tree for RZ/G2L family SoCs is "renesas,rzg2l-sdhi"
not "renesas,rcar-gen3-sdhi". This broke the ability to access the eMMC
and SD card devices on RZ/G2L boards.

Fix this by adding the new compatible string to the sdhi driver.

Fixes: 136b7b6d2e98 ("Subtree merge tag 'v6.11-dts' of dts repo [1] into dts/upstream")
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>