drm/nouveau/disp: fix cast removes address space of expression warnings

When build Linux kernel with 'make C=2', encounter the following warnings:

./drivers/gpu/drm/nouveau/dispnv50/disp.c:134:34: warning: cast removes address space '__iomem' of expression
./drivers/gpu/drm/nouveau/dispnv50/disp.c:197:34: warning: cast removes address space '__iomem' of expression

The data type of dmac->_push.mem.object.map.ptr is 'void __iomem *', but
converted to 'u32 *' directly and cause above warnings, now
recover their data types to fix these warnings.
Signed-off-by: ruanjinjie <ruanjinjie@huawei.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220924092516.10007-1-ruanjinjie@huawei.com

drivers/gpu/drm/nouveau/dispnv50/disp.c

@@ -131,7 +131,7 @@ nv50_dmac_kick(struct nvif_push *push)
 {
 	struct nv50_dmac *dmac = container_of(push, typeof(*dmac), _push);
 
-	dmac->cur = push->cur - (u32 *)dmac->_push.mem.object.map.ptr;
+	dmac->cur = push->cur - (u32 __iomem *)dmac->_push.mem.object.map.ptr;
 	if (dmac->put != dmac->cur) {
 		/* Push buffer fetches are not coherent with BAR1, we need to ensure
 		 * writes have been flushed right through to VRAM before writing PUT.
@@ -194,7 +194,7 @@ nv50_dmac_wait(struct nvif_push *push, u32 size)
 	if (WARN_ON(size > dmac->max))
 		return -EINVAL;
 
-	dmac->cur = push->cur - (u32 *)dmac->_push.mem.object.map.ptr;
+	dmac->cur = push->cur - (u32 __iomem *)dmac->_push.mem.object.map.ptr;
 	if (dmac->cur + size >= dmac->max) {
 		int ret = nv50_dmac_wind(dmac);
 		if (ret)