pinctrl: sh-pfc: r8a7795: Add group for QSPI0 and QSPI1 pins

Group the QSPI0 and QSPI1 pins into similar groups found in other sh-pfc
drivers. The pins can not be muxed between functions other than QSPI,
but their drive strength can be controlled.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>