gpio: sunxi: Add compatible string for H5 PIO

Add allwinner,sun50i-h5-pinctrl compatible for H5 boards.

Signed-off-by: Chris Blake <chrisrblake93@gmail.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
[jagan: remove external link and format commit message]
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>