irq: trivial: Fix typo in comment for #endif

The comment suggests this #endif is CONFIG_X86 but it's really
CONFIG_TRACE_IRQFLAGS_SUPPORT

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: michael@ellerman.id.au
LKML-Reference: <18191.1256182768@neuling.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>