app/testpmd: revert fixed flag for exact link speed
app/testpmd: revert fixed flag for exact link speed

This reverts commit bdca79053b6aea504d02691d9319fa976062457f.

Not all PMDs support the fixed link speed set, and link speed can be set
even with auto negotiation enabled. Reverting the patch to not break
existing usage.

Fixes: bdca79053b6a ("app/testpmd: set fixed flag for exact link speed")
Cc: stable@dpdk.org

Signed-off-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk