perf: Update MAINTAINERS for x86 move

The move of the x86 perf implementation forgot to update the MAINTAINERS
F(ile) pattern.

Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Acked-by: Borislav Petkov <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Fixes: fa9cbf320e99 ("perf/x86: Move perf_event.c ............... => x86/events/core.c")
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

MAINTAINERS

···
 F:	arch/*/kernel/*/*/perf_event*.c
 F:	arch/*/include/asm/perf_event.h
 F:	arch/*/kernel/perf_callchain.c
+F:	arch/*/events/*
 F:	tools/perf/
 
 PERSONALITY HANDLING