[ARM] remove memzero()

As suggested by Andrew Morton, remove memzero() - it's not supported
on other architectures so use of it is a potential build breaking bug.
Since the compiler optimizes memset(x,0,n) to __memzero() perfectly
well, we don't miss out on the underlying benefits of memzero().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/mmu.c

@@ -896,7 +896,7 @@ void __init paging_init(struct meminfo *mi, struct machine_desc *mdesc)
 	 * allocate the zero page.  Note that we count on this going ok.
 	 */
 	zero_page = alloc_bootmem_low_pages(PAGE_SIZE);
-	memzero(zero_page, PAGE_SIZE);
+	memset(zero_page, 0, PAGE_SIZE);
 	empty_zero_page = virt_to_page(zero_page);
 	flush_dcache_page(empty_zero_page);
 }