dracut: Add drivers/clk by default on arm

dracut: Add drivers/clk by default on arm

This will bundle clock drivers into the initramfs on arm

Tested on ti dm8148-t410 where adpll is needed on 4.6+ kernel
This will avoid to rely on (maybe broken) bootloader clocks.

Theses modules are also usually loaded early. Having them bundled into
the initramfs will avoid lot of deferred probes and others delay.

Signed-off-by: Nicolas Chauvet <kwizart@gmail.com>