The value of ec_mdata cannot be NULL, instead check that value of
private_data_offset was set.
Coverity issue: 378861, 378865
Fixes: 97ebfda82910 ("crypto/cnxk: add event metadata set operation")
Signed-off-by: Volodymyr Fialko <vfialko@marvell.com>
Acked-by: Anoob Joseph <anoobj@marvell.com>