arm64: dts: renesas: r8a77995: draak: Fix backlight regulator name

Currently there are two nodes named "regulator1" in the Draak DTS: a
3.3V regulator for the eMMC and the LVDS decoder, and a 12V regulator
for the backlight.  This causes the former to be overwritten by the
latter.

Fix this by renaming all regulators with numerical suffixes to use named
suffixes, which are less likely to conflict.

Fixes: 4fbd4158 ("arm64: dts: renesas: r8a77995: draak: Add backlight")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>