staging: rtl8192e: don't just print an error and continue

I was looking at how TOTAL_CAM_ENTRY is used and I saw this code.  We
print an error but continue writing "EntryNo" to a register as if it
were valid.  "EntryNo" is controlled by the user in rtl8192_ioctl() so
it definitely can be invalid.  I'm not positive what happens with the
invalid data but it can't be good.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>