ARM: l2c: vexpress ca9x4: move L2 cache initialisation earlier

It is beneficial to have the L2 cache up and running earlier in the
system boot.  Not only will this allow for simpler code when we come to
enable some features, but it also means that we get a more accurate
bogomips value for the udelay() loop.  Calibrating the loop with the
L2 cache off, and then running with the L2 cache on is not the best
idea.

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