ARM: dts: lager: Name spi pfc subnodes after device names

Name the Pin Function Controller subnodes for QSPI and MSIOF1 after
their device names, instead of after the spi interface aliases.

This avoids conflicts when enabling support for more spi interfaces
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>