can: m_can: Move accessing of message ram to after clocks are enabled

MCAN message ram should only be accessed once clocks are enabled.
Therefore, move the call to parse/init the message ram to after
clocks are enabled.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>