qlxgbe: fix debug prints in ql_os.c
QL_DPRINT2 checks the debug level first and then prints.
Replace device_printf with QL_DPRINT2 to check debug level
first before printing out the kernel pointers.
PR: 238655
(cherry picked from commit 3d6c7ee87e9d7f3c8f617c3803af3effa8eb8a16)