ARM: 6946/1: vexpress: move v2m clock init to init_early

Commit 7ff550de99141cbd3be0129d563cc4554fdde9f6 breaks vexpress booting. The
v2m clock table needs to be setup in init_early before the timer
initialization occurs.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>