board_f: Use timer_init() on all archs

More than half of the architectures use this function so let's make them
all use it.

For those which don't actually define it, we can rely on the weak function
in lib/time.c

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: York Sun <york.sun@nxp.com>
Reviewed-by: Stefan Roese <sr@denx.de>