Caught by clang, this idx value is only used for a debug message when
the mbufs allocation fails.
No need to use idx as a temporary storage.
Fixes: 8f2312474529 ("net/qede: fix performance bottleneck in Rx path")
Cc: stable@dpdk.org
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Rasesh Mody <rmody@marvell.com>