e1000e: fix call to do_div() to use u64 arg
e1000e: fix call to do_div() to use u64 arg

We were using s64 for lat_ns (latency nano-second value) since in
our calculations a negative value could be a resultant.  For negative
values, we then assign lat_ns to be zero, so the value passed to
do_div() was never negative, but do_div() expects the argument type
to be u64, so do a cast to resolve a compile warning seen on
PowerPC.

CC: Yanjiang Jin <75ec4c3842c6f7189a6ead1c4899bf8a25b6bbb2@windriver.com>
CC: Yanir Lubetkin <92610f7d2a881e373b47a48d6a67b431fc0c1511@intel.com>
Reported-by: Yanjiang Jin <75ec4c3842c6f7189a6ead1c4899bf8a25b6bbb2@windriver.com>
Signed-off-by: Jeff Kirsher <87e35f5be20bb3e67f4ba6b86f5f6be3085b1b3a@intel.com>
Tested-by: Aaron Brown <4723df1d9a4136f7b76e1bf6434e33afc91d2139@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs