can: gs_usb: codingstyle: introduce use of BIT() + fix indention

This patch converts "1 << n" by BIT(n) and fixes the indention. No
functional change.

Signed-off-by: Hubert Denkmair <hubert@denkmair.de>
Signed-off-by: Maximilian Schneider <max@schneidersoft.net>
[mkl: split codingstyle changes into separate patch]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>