can: mscan: remove unused struct 'mscan_state'

'mscan_state' is unused since the original
commit afa17a50 ("net/can: add driver for mscan family &
mpc52xx_mscan").

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/all/20240525232509.191735-1-linux@treblig.org


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>