buildtools: fix AVX512 check for Python 3.5

Python 3.5 subprocess.run() does not have a capture_output
parameter (it is present only in 3.7 and up).
Capture output by using subprocess.PIPE for stdout instead.

Fixes: bb9cd91095 ("buildtools: make AVX512 check portable")
Cc: stable@dpdk.org

Signed-off-by: Lance Richardson <lance.richardson@broadcom.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>

buildtools/binutils-avx512-check.py

@@ -15,7 +15,7 @@
     src = '__asm__("vpgatherqq {}");'.format(gather_params).encode('utf-8')
     subprocess.run(cc + ['-c', '-xc', '-o', obj.name, '-'], input=src, check=True)
     asm = subprocess.run([objdump, '-d', '--no-show-raw-insn', obj.name],
-                         capture_output=True, check=True).stdout.decode('utf-8')
+                         stdout=subprocess.PIPE, check=True).stdout.decode('utf-8')
     if gather_params not in asm:
 	    print('vpgatherqq displacement error with as')
 	    sys.exit(1)