During LTO build compiler reports some 'false positive' warnings about
variables being possibly used uninitialized. This patch silences these
warnings.
Exemplary compiler warning to suppress (with LTO enabled):
error: ‘filter_idx’ may be used uninitialized in this function
[-Werror=maybe-uninitialized]
PMD_DRV_LOG(INFO, "Added port %d with AQ command with index %d",
Signed-off-by: Andrzej Ostruszka <aostruszka@marvell.com>