ixgbe/base: use a semaphore to serialize X550 IOSF accesses
ixgbe/base: use a semaphore to serialize X550 IOSF accesses

Because each IOSF access requires the use of multiple registers,
use a semaphore to serialize those accesses.

Signed-off-by: Wenzhuo Lu <58cb9036bdff9a5412edc3b9f70e105ccf59954f@intel.com>
Acked-by: Helin Zhang <aba9dfdb1a6ec8bf1ff66b95272c029f8dfde1b1@intel.com>

john-mcnamara-intel/dpdk,msune/dpdk,mixja/dpdk,john-mcnamara-intel/dpdk,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,msune/dpdk,tsphillips/dpdk-fork,tsphillips/dpdk-fork,tsphillips/dpdk-fork,mixja/dpdk,tsphillips/dpdk-fork,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,msune/dpdk,venkynv/dpdk-mirror,mixja/dpdk,mixja/dpdk,msune/dpdk,venkynv/dpdk-mirror