net: dsa: rzn1_a5psw: add COMPILE_TEST

There's no architecture specific requirement for it to compile. Allows
the bots to test compilation properly.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250708014144.2514-2-rosenp@gmail.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>