m68k: m5441x: add flexcan support

Add flexcan support.

Signed-off-by: Angelo Dureghello <angelo@kernel-space.org>

Made the flexcan resource inclusion conditional based on the enablement
of the flexcan driver. This commit is no longer dependant on the
presence of the updated driver in mainline.

Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>