This fixes the following newly introduced warning:

[   15.518253] ------------[ cut here ]------------
[   15.518941] WARNING: CPU: 0 PID: 246 at kernel/dma/mapping.c:149 dma_map_page_attrs+0x1a8/0x1d0
[   15.520634] Modules linked in: pwc videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common videodev mc efivarfs
[   15.522335] CPU: 0 PID: 246 Comm: v4l2-test Not tainted 5.11.0-rc1+ #1
[   15.523281] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[   15.524438] RIP: 0010:dma_map_page_attrs+0x1a8/0x1d0
[   15.525135] Code: 10 5b 5d 41 5c 41 5d c3 4d 89 d0 eb d7 4d 89 c8 89 e9 48 89 da e8 68 29 00 00 eb d1 48 89 f2 48 2b 50 18 48 89 d0 eb 83 0f 0b <0f> 0b 48 c7 c0 ff ff ff ff eb b8 48 89 d9 48 8b 40 40 e8 61 69 d2
[   15.527938] RSP: 0018:ffffa2694047bca8 EFLAGS: 00010246
[   15.528716] RAX: 0000000000000000 RBX: 0000000000002580 RCX: 0000000000000000
[   15.529782] RDX: 0000000000000000 RSI: ffffcdce000ecc00 RDI: ffffa0b4bdb888a0
[   15.530849] RBP: 0000000000000002 R08: 0000000000000002 R09: 0000000000000000
[   15.531881] R10: 0000000000000004 R11: 000000000002d8c0 R12: 0000000000000000
[   15.532911] R13: ffffa0b4bdb88800 R14: ffffa0b483820000 R15: ffffa0b4bdb888a0
[   15.533942] FS:  00007fc5fbb5e4c0(0000) GS:ffffa0b4fc000000(0000) knlGS:0000000000000000
[   15.535141] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.535988] CR2: 00007fc5fb6ea138 CR3: 0000000003812000 CR4: 00000000001506f0
[   15.537025] Call Trace:
[   15.537425]  start_streaming+0x2e9/0x4b0 [pwc]
[   15.538143]  vb2_start_streaming+0x5e/0x110 [videobuf2_common]
[   15.538989]  vb2_core_streamon+0x107/0x140 [videobuf2_common]
[   15.539831]  __video_do_ioctl+0x18f/0x4a0 [videodev]
[   15.540670]  video_usercopy+0x13a/0x5b0 [videodev]
[   15.541349]  ? video_put_user+0x230/0x230 [videodev]
[   15.542096]  ? selinux_file_ioctl+0x143/0x200
[   15.542752]  v4l2_ioctl+0x40/0x50 [videodev]
[   15.543360]  __x64_sys_ioctl+0x89/0xc0
[   15.543930]  do_syscall_64+0x33/0x40
[   15.544448]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   15.545236] RIP: 0033:0x7fc5fb671587
[   15.545780] Code: b3 66 90 48 8b 05 11 49 2c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 48 2c 00 f7 d8 64 89 01 48
[   15.548486] RSP: 002b:00007fff0f71f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[   15.549578] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fc5fb671587
[   15.550664] RDX: 00007fff0f71f060 RSI: 0000000040045612 RDI: 0000000000000003
[   15.551706] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[   15.552738] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff0f71f060
[   15.553817] R13: 00007fff0f71f1d0 R14: 0000000000de1270 R15: 0000000000000000
[   15.554914] ---[ end trace 7be03122966c2486 ]---

Fixes: 1161db67 ("media: usb: pwc: Don't use coherent DMA buffers for ISO transfer")
Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>