sfxge(4): cleanup: remove unused EFX preempt macros

The EFSYS_PREEMPT_DISABLE() and EFSYS_PREEMPT_ENABLE() macros
were used to ensure correct timing of I2C operations. The APIs
for I2C operations have been removed, so these macros have no
callers.

Submitted by:   Andy Moreton <amoreton at solarflare.com>
Sponsored by:   Solarflare Communications, Inc.
MFC after:      1 week

sys/dev/sfxge/common/efsys.h

@@ -1110,22 +1110,6 @@ typedef struct efsys_lock_s {
 	_NOTE(CONSTANTCONDITION)					\
 	} while (B_FALSE)
 
-/* PREEMPT */
-
-#define	EFSYS_PREEMPT_DISABLE(_state)					\
-	do {								\
-		(_state) = (_state);					\
-		critical_enter();					\
-	_NOTE(CONSTANTCONDITION)					\
-	} while (B_FALSE)
-
-#define	EFSYS_PREEMPT_ENABLE(_state)					\
-	do {								\
-		(_state) = (_state);					\
-		critical_exit(_state);					\
-	_NOTE(CONSTANTCONDITION)					\
-	} while (B_FALSE)
-
 /* STAT */
 
 typedef uint64_t		efsys_stat_t;