proc: switch /proc/meminfo to seq_file

and move it to fs/proc/meminfo.c while I'm at it.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

mm/hugetlb.c

@@ -7,6 +7,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mm.h>
+#include <linux/seq_file.h>
 #include <linux/sysctl.h>
 #include <linux/highmem.h>
 #include <linux/mmu_notifier.h>
@@ -1455,10 +1456,10 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write,
 
 #endif /* CONFIG_SYSCTL */
 
-int hugetlb_report_meminfo(char *buf)
+void hugetlb_report_meminfo(struct seq_file *m)
 {
 	struct hstate *h = &default_hstate;
-	return sprintf(buf,
+	seq_printf(m,
 			"HugePages_Total:   %5lu\n"
 			"HugePages_Free:    %5lu\n"
 			"HugePages_Rsvd:    %5lu\n"