xen: Convert printks to pr_<level>

Convert printks to pr_<level> (excludes printk(KERN_DEBUG...)
to be more consistent throughout the xen subsystem.

Add pr_fmt with KBUILD_MODNAME or "xen:" KBUILD_MODNAME
Coalesce formats and add missing word spaces
Add missing newlines
Align arguments and reflow to 80 columns
Remove DRV_NAME from formats as pr_fmt adds the same content

This does change some of the prefixes of these messages
but it also does make them more consistent.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/balloon.c

@@ -36,6 +36,8 @@
  * IN THE SOFTWARE.
  */
 
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/errno.h>
@@ -242,7 +244,7 @@ static enum bp_state reserve_additional_memory(long credit)
 	rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT);
 
 	if (rc) {
-		pr_info("xen_balloon: %s: add_memory() failed: %i\n", __func__, rc);
+		pr_info("%s: add_memory() failed: %i\n", __func__, rc);
 		return BP_EAGAIN;
 	}
 
@@ -591,7 +593,7 @@ static int __init balloon_init(void)
 	if (!xen_domain())
 		return -ENODEV;
 
-	pr_info("xen/balloon: Initialising balloon driver.\n");
+	pr_info("Initialising balloon driver\n");
 
 	balloon_stats.current_pages = xen_pv_domain()
 		? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)