mem: fix error message with Xen
mem: fix error message with Xen

Minor typo fix to error message

Fixes: 148f963fb532 ("xen: core library changes")

Signed-off-by: Marcin Kerlin <3bfb32e41d7a426ef20ce0195dad34f5c9a449f6@intel.com>

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