pinctrl: renesas: r8a779g0: Fix IRQ suffixes

The suffixes of the IRQ identifiers for external interrupts 0-3
are inconsistent:
  - "IRQ0" and "IRQ0_A",
  - "IRQ1" and "IRQ1_A",
  - "IRQ2" and "IRQ2_A",
  - "IRQ3" and "IRQ3_B".
The suffixes for external interrupts 4 and 5 do follow conventional
naming:
  - "IRQ4A" and IRQ4_B",
  - "IRQ5".

Fix this by adopting R-Car V4M naming:
  - Rename "IRQ[0-2]_A" to "IRQ[0-2]_B",
  - Rename "IRQ[0-3]" to "IRQ[0-3]_A".

Fixes: ad9bb2fe ("pinctrl: renesas: Initial R8A779G0 (R-Car V4H) PFC support")
Fixes: 1b23d8a4 ("pinctrl: renesas: r8a779g0: Add missing IRQx_A/IRQx_B")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/8ce9baf0a0f9346544a3ac801fd962c7c12fd247.1717754960.git.geert+renesas@glider.be