Fix 32-bit build post 6733401935f83754b4b2744bc3d33ef84b1271e0

The general style in sbin/nvmecontrol apppears to print uint64_t types
using %j, so I'm using that instead of the more general (but admittedly
ugly) PRIu64.

(cherry picked from commit a82f07fc2e2456b0ddc847d611f56a3152a6f940)