ARM: 7529/1: delay: set loops_per_jiffy when moving to timer-based loop

The delay functions may be called by some platforms between switching to
the timer-based delay loop but before calibration. In this case, the
initial loops_per_jiffy may not be suitable for the timer (although a
compromise may be achievable) and delay times may be considered too
inaccurate.

This patch updates loops_per_jiffy when switching to the timer-based
delay loop so that delays are consistent prior to calibration.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>