perf: fix x86 compilation fix

perf: fix x86 compilation fix

CC util/session.o
cc1: warnings being treated as errors
util/session.c: In function 'perf_session_deliver_event':
util/include/linux/bitops.h:108: error: dereferencing pointer 'p' does break strict-aliasing rules
util/include/linux/bitops.h:100: error: dereferencing pointer 'p' does break strict-aliasing rules
util/session.c:923: note: initialized from here
util/include/linux/bitops.h:100: note: initialized from here
make: *** [util/session.o] Error 1