ARM: dts: lager: Name serial port pfc subnodes after device names

Name the Pin Function Controller subnodes for SCIF0 and SCIFA1 after
their device names, instead of after the serial port aliases.

This avoids conflicts when enabling support for more serial ports later,
either here or in a DT overlay.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>