drivers: net: smc911x: Fix set but unused status because of DBG macro

drivers/net/ethernet/smsc/smc911x.c: In function ‘smc911x_timeout’:
drivers/net/ethernet/smsc/smc911x.c:1251:6: warning: variable ‘status’ set but not used [-Wunused-but-set-variable]
 1251 |  int status, mask;

The status is read in order to print it via the DBG macro. However,
due to the way DBG is disabled, the compiler never sees it being used.

Change the DBG macro to actually make use of the passed parameters,
and the leave the optimiser to remove the unwanted code inside the
while (0).

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>