mm: change_memory_common: add spaces for `*` operator

Leaves one space before and after a binary operator both, it may be more elegant.
Signed-off-by: NPan Zhang <zhangpan26@huawei.com>
Signed-off-by: NWill Deacon <will@kernel.org>

arch/arm64/mm/pageattr.c

@@ -54,7 +54,7 @@ static int change_memory_common(unsigned long addr, int numpages,
 				pgprot_t set_mask, pgprot_t clear_mask)
 {
 	unsigned long start = addr;
-	unsigned long size = PAGE_SIZE*numpages;
+	unsigned long size = PAGE_SIZE * numpages;
 	unsigned long end = start + size;
 	struct vm_struct *area;
 	int i;