arm64: dts: renesas: r8a77990: ebisu: Fix backlight regulator numbering

There are two regulator1 nodes in the Ebisu DTS right now, one 3.3V for
the eMMC and one 12V for the backlight. This causes one to be overwritten
by the other, ultimatelly resulting in inoperable eMMC, which depends on
the former. Fix this by renumbering the backlight regulator to regulator2.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Reported-by: Simon Horman <horms+renesas@verge.net.au>
Fixes: 9d16c4a1 ("arm64: dts: renesas: r8a77990: ebisu: Add backlight")
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>