misc: aspeed-p2a-ctrl: fix mixed declarations

Fix up mixed declarations and code in aspeed_p2a_mmap.

Tested: Verified the build had the error and that this patch resolved it
and there were no other warnings or build errors associated with
compilation of this driver.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Patrick Venture <venture@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/aspeed-p2a-ctrl.c

@@ -100,6 +100,7 @@ static void aspeed_p2a_disable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl)
 static int aspeed_p2a_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	unsigned long vsize;
+	pgprot_t prot;
 	struct aspeed_p2a_user *priv = file->private_data;
 	struct aspeed_p2a_ctrl *ctrl = priv->parent;
 
@@ -107,7 +108,7 @@ static int aspeed_p2a_mmap(struct file *file, struct vm_area_struct *vma)
 		return -EINVAL;
 
 	vsize = vma->vm_end - vma->vm_start;
-	pgprot_t prot = vma->vm_page_prot;
+	prot = vma->vm_page_prot;
 
 	if (vma->vm_pgoff + vsize > ctrl->mem_base + ctrl->mem_size)
 		return -EINVAL;