ARM: 9280/1: mm: fix warning on phys_addr_t to void pointer assignment

zero_page is a void* pointer but memblock_alloc() returns phys_addr_t type
so this generates a warning while using clang and with -Wint-error enabled
that becomes and error. So let's cast the return of memblock_alloc() to
(void *).

Cc: <stable@vger.kernel.org> # 4.14.x +
Fixes: 340a9828 ("ARM: 9266/1: mm: fix no-MMU ZERO_PAGE() implementation")
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

arch/arm/mm/nommu.c

@@ -161,7 +161,7 @@ void __init paging_init(const struct machine_desc *mdesc)
 	mpu_setup();
 
 	/* allocate the zero page. */
-	zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+	zero_page = (void *)memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 	if (!zero_page)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 		      __func__, PAGE_SIZE, PAGE_SIZE);