pinctrl: renesas: r8a779g0: Fix Group 6/7 pin functions

pinctrl: renesas: r8a779g0: Fix Group 6/7 pin functions

According to R-Car V4H Series User’s Manual: Hardware Rev. 0.54, pin
groups 6 and 7 do not use Module Select Registers to configure pin
functions.

Hence:
  - Remove the non-existent Module Select Registers (MODSEL[67]),
  - Correct the affected PINMUX definitions.

Fixes: 36611d28f5130d8b ("pinctrl: renesas: r8a779g0: Add missing MODSELx for AVBx")
Fixes: ad9bb2fec66262b0 ("pinctrl: renesas: Initial R8A779G0 (R-Car V4H) PFC support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/06972cafd0efa4cfb395cfa76000a1bdae5e9e73.1669036423.git.geert+renesas@glider.be