octeontx2-af: Fix undetected unmap PF error check

Currently the check for an unmap PF error is always going to be false
because intr_val is a 32 bit int and is being bit-mask checked against
1ULL << 32.  Fix this by making intr_val a u64 to match the type at it
is copied from, namely npa_event_context->npa_af_rvu_ge.

Addresses-Coverity: ("Operands don't affect result")
Fixes: f1168d1e

 ("octeontx2-af: Add devlink health reporters for NPA")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: George Cherian <george.cherian@marvell.com>
Link: https://lore.kernel.org/r/20201216123604.15369-1-colin.king@canonical.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>