src/include: Add space after comma

Fix the following error detected by checkpatch.pl:

ERROR: space required after that ',' (ctx:VxV)

TEST=Build and run on Galileo Gen2

Change-Id: I297bfc3d03dc95b471d3bb4b13803e81963841b5
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/18647
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/include/device/pci.h

@@ -54,7 +54,7 @@ struct pci_driver {
 	const unsigned short *devices;
 };
 
-#define __pci_driver __attribute__ ((used,__section__(".rodata.pci_driver")))
+#define __pci_driver __attribute__ ((used, __section__(".rodata.pci_driver")))
 /** start of compile time generated pci driver array */
 extern struct pci_driver _pci_drivers[];
 /** end of compile time generated pci driver array */