perf: Normalize gcc parameter when generating arch errno table

perf: Normalize gcc parameter when generating arch errno table

The $(CC) passed to arch_errno_names.sh may include a series of parameters
along with gcc itself. To avoid overwriting the following parameters of
arch_errno_names.sh and break the build like below, we just pick up the
first word of the $(CC).

  find: unknown predicate `-m64/arch'
  x86_64-wrs-linux-gcc: warning: '-x c' after last input file has no effect
  x86_64-wrs-linux-gcc: error: unrecognized command line option '-m64/include/uapi/asm-generic/errno.h'
  x86_64-wrs-linux-gcc: fatal error: no input files

Signed-off-by: He Zhe <zhe.he@windriver.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/1581618066-187262-2-git-send-email-zhe.he@windriver.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>