arch/um/kernel/mem.c: fix a shadowed variable

Fix a shadowed variable in arch/um/kernel/mem.c, since there is a global
variable has the same name.

Cc: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/kernel/mem.c

@@ -299,7 +299,7 @@ void show_mem(void)
 {
 	int pfn, total = 0, reserved = 0;
 	int shared = 0, cached = 0;
-	int highmem = 0;
+	int high_mem = 0;
 	struct page *page;
 
 	printk(KERN_INFO "Mem-info:\n");
@@ -311,7 +311,7 @@ void show_mem(void)
 		page = pfn_to_page(pfn);
 		total++;
 		if (PageHighMem(page))
-			highmem++;
+			high_mem++;
 		if (PageReserved(page))
 			reserved++;
 		else if (PageSwapCache(page))
@@ -320,7 +320,7 @@ void show_mem(void)
 			shared += page_count(page) - 1;
 	}
 	printk(KERN_INFO "%d pages of RAM\n", total);
-	printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
+	printk(KERN_INFO "%d pages of HIGHMEM\n", high_mem);
 	printk(KERN_INFO "%d reserved pages\n", reserved);
 	printk(KERN_INFO "%d pages shared\n", shared);
 	printk(KERN_INFO "%d pages swap cached\n", cached);