sfc: Make all CPU/IRQ/channel/queue counts unsigned

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 59c0583..3260e71 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -52,7 +52,7 @@
  *
  **************************************************************************/
 
-#define EFX_MAX_CHANNELS 32
+#define EFX_MAX_CHANNELS 32U
 #define EFX_MAX_RX_QUEUES EFX_MAX_CHANNELS
 
 /* Checksum generation is a per-queue option in hardware, so each