net: dsa: microchip: Fix wrong rx drop MIB counter for KSZ8863

net: dsa: microchip: Fix wrong rx drop MIB counter for KSZ8863

When KSZ8863 support was first added to KSZ driver the RX drop MIB
counter was somehow defined as 0x105.  The TX drop MIB counter
starts at 0x100 for port 1, 0x101 for port 2, and 0x102 for port 3, so
the RX drop MIB counter should start at 0x103 for port 1, 0x104 for
port 2, and 0x105 for port 3.

There are 5 ports for KSZ8895, so its RX drop MIB counter starts at
0x105.

Fixes: 4b20a07e103f ("net: dsa: microchip: ksz8795: add support for ksz88xx chips")
Signed-off-by: Tristram Ha <tristram.ha@microchip.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20250723030403.56878-1-Tristram.Ha@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>