ARM: dts: renesas: porter: Fix CAN pin group

[ Upstream commit 287066b2 ]

According to the schematics, the CAN transceiver is connected to pins
GP7_3 and GP7_4, which correspond to CAN0 data group B.

Fixes: 0768fbad ("ARM: shmobile: porter: add CAN0 DT support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/70ad9bc44d6cea92197c42eedcad6b3d0641d26a.1751032025.git.geert+renesas@glider.be


Signed-off-by: Sasha Levin <sashal@kernel.org>