uboot-phytec

pinctrl: renesas: Fix DRV register offset

Use fixed 4bit size for generating the DRV register element mask,
not the size of the value, which can be smaller.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>