sfc: Fix some formatting errors reported by checkpatch

Fix the following errors and warnings:

ERROR: trailing whitespace
ERROR: spaces required around that '=' (ctx:VxV)
WARNING: please, no space before tabs

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/spi.h b/drivers/net/ethernet/sfc/spi.h
index 71f2e3e..5431a1b 100644
--- a/drivers/net/ethernet/sfc/spi.h
+++ b/drivers/net/ethernet/sfc/spi.h
@@ -68,7 +68,7 @@
 
 int falcon_spi_cmd(struct efx_nic *efx,
 		   const struct efx_spi_device *spi, unsigned int command,
-		   int address, const void* in, void *out, size_t len);
+		   int address, const void *in, void *out, size_t len);
 int falcon_spi_wait_write(struct efx_nic *efx,
 			  const struct efx_spi_device *spi);
 int falcon_spi_read(struct efx_nic *efx,