ARM: remove obsolete smp_cross_call_done()

smp_cross_call_done() was removed long ago (see 78d236c2 - remove useless
smp_cross_call_done()).  Remove those which have been subsequently
merged.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-tegra/include/mach/smp.h

@@ -12,11 +12,4 @@ static inline void smp_cross_call(const struct cpumask *mask)
 	gic_raise_softirq(mask, 1);
 }
 
-/*
- * Do nothing on MPcore.
- */
-static inline void smp_cross_call_done(cpumask_t callmap)
-{
-}
-
 #endif