ARM: integrator: fix compile warning in cpu.c

Fix:
arch/arm/mach-integrator/cpu.c: In function ■integrator_get■:
arch/arm/mach-integrator/cpu.c:164: warning: ■vco.s■ may be used uninitialized in this function

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