mac80211: fix spare warnings in driver-trace.h

This patch fixes the following errors:

driver-trace.h:148:1: error: cannot size expression
driver-trace.h:148:1: error: cannot size expression
[...]
driver-trace.h:222:1: error: cannot size expression
driver-trace.h:71:1: error: incompatible types for operation (<)
driver-trace.h:71:1:    left side has type void *<noident>
driver-trace.h:71:1:    right side has type int
driver-trace.h:99:1: error: incompatible types for operation (<)
driver-trace.h:99:1:    left side has type void *<noident>
driver-trace.h:99:1:    right side has type int
driver-trace.h:148:1: error: incompatible types for operation (<)
driver-trace.h:148:1:    left side has type void *<noident>
driver-trace.h:148:1:    right side has type int
driver-trace.h:222:1: error: cannot size expression
driver-trace.h:248:1: error: incompatible types for operation (<)
driver-trace.h:248:1:    left side has type void *<noident>
driver-trace.h:248:1:    right side has type int
driver-trace.h:446:1: error: incompatible types for operation (<)
driver-trace.h:446:1:    left side has type void *<noident>
driver-trace.h:446:1:    right side has type int

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>