A recent change removed errno.h from rte_common.h.
x86 EAL headers seem to include it (probably via
rte_spinlock/rte_cpuflags) but other architectures won't.
Add an explicit inclusion.
Fixes: d826133ae8 ("net/octeon_ep: support CN10K SoC")
Signed-off-by: David Marchand <david.marchand@redhat.com>