can: grcan: move napi_enable() from under spin lock

I don't see any reason why napi_enable() needs to be under the lock,
only reason I could think of is if the IRQ also took this lock
but it doesn't. napi_enable() will soon need to sleep.

Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Reviewed-by: Francois Romieu <romieu@fr.zoreil.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://patch.msgid.link/20250111024742.3680902-1-kuba@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>