[ARM] Provide basic printk_clock() implementation

Current sched_clock() implementations on ARM cause unbootable kernels
with PRINTK_TIME support enabled.  To avoid this, provide a basic
printk_clock() implementation which avoids sched_clock() being called
before the page tables have been set up.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
1 file changed