perf build: Remove x86 references from arch-neutral Build

perf build: Remove x86 references from arch-neutral Build

It will already be dealt with generating the syscalltbl.c file in the
x86 arch specific Build files, namely via 'archheaders'.

This fixes the build on !x86 arches, as reported for powerpcle

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 1b700c997500 ("perf tools: Build syscall table .c header from kernel's syscall_64.tbl")
Link: http://lkml.kernel.org/r/20160415212831.GT9056@kernel.org
[ Removed the syscalltbl.o altogether, as per Jiri's suggestion ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>