bpf tools: Remove expression with no effect

Assigning "attr" to "attr" does not have any effect, but was caught by
Coverity, so let's remove this.

Reported-by: coverity (CID 1354720)
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Fixes: 1b76c13e4b ("bpf tools: Introduce 'bpf' library and add bpf feature check")
Link: http://lkml.kernel.org/r/1461551694-5512-2-git-send-email-f.fainelli@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/build/feature/test-bpf.c

@@ -27,7 +27,6 @@ int main(void)
 	attr.log_level = 0;
 	attr.kern_version = 0;
 
-	attr = attr;
 	/*
 	 * Test existence of __NR_bpf and BPF_PROG_LOAD.
 	 * This call should fail if we run the testcase.