nouveau/firmware: use dma non-coherent allocator

In the Linux kernel, the following vulnerability has been resolved:

nouveau/firmware: use dma non-coherent allocator

Currently, enabling SG_DEBUG in the kernel will cause nouveau to hit a

BUG() on startup, when the iommu is enabled:

kernel BUG at include/linux/scatterlist.h:187!

invalid opcode: 0000 [#1] PREEMPT SMP NOPTI

CPU: 7 PID: 930 Comm: (udev-worker) Not tainted 6.9.0-rc3Lyude-Test+ #30

Hardware name: MSI MS-7A39/A320M GAMING PRO (MS-7A39), BIOS 1.I0 01/22/2019

RIP: 0010:sg_init_one+0x85/0xa0

Code: 69 88 32 01 83 e1 03 f6 c3 03 75 20 a8 01 75 1e 48 09 cb 41 89 54

24 08 49 89 1c 24 41 89 6c 24 0c 5b 5d 41 5c e9 7b b9 88 00 <0f> 0b 0f 0b

0f 0b 48 8b 05 5e 46 9a 01 eb b2 66 66 2e 0f 1f 84 00

RSP: 0018:ffffa776017bf6a0 EFLAGS: 00010246

RAX: 0000000000000000 RBX: ffffa77600d87000 RCX: 000000000000002b

RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffa77680d87000

RBP: 000000000000e000 R08: 0000000000000000 R09: 0000000000000000

R10: ffff98f4c46aa508 R11: 0000000000000000 R12: ffff98f4c46aa508

R13: ffff98f4c46aa008 R14: ffffa77600d4a000 R15: ffffa77600d4a018

FS: 00007feeb5aae980(0000) GS:ffff98f5c4dc0000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f22cb9a4520 CR3: 00000001043ba000 CR4: 00000000003506f0

Call Trace:

<TASK>

? die+0x36/0x90

? do_trap+0xdd/0x100

? sg_init_one+0x85/0xa0

? do_error_trap+0x65/0x80

? sg_init_one+0x85/0xa0

? exc_invalid_op+0x50/0x70

? sg_init_one+0x85/0xa0

? asm_exc_invalid_op+0x1a/0x20

? sg_init_one+0x85/0xa0

nvkm_firmware_ctor+0x14a/0x250 [nouveau]

nvkm_falcon_fw_ctor+0x42/0x70 [nouveau]

ga102_gsp_booter_ctor+0xb4/0x1a0 [nouveau]

r535_gsp_oneinit+0xb3/0x15f0 [nouveau]

? srso_return_thunk+0x5/0x5f

? srso_return_thunk+0x5/0x5f

? nvkm_udevice_new+0x95/0x140 [nouveau]

? srso_return_thunk+0x5/0x5f

? srso_return_thunk+0x5/0x5f

? ktime_get+0x47/0xb0

Fix this by using the non-coherent allocator instead, I think there

might be a better answer to this, but it involve ripping up some of

APIs using sg lists.