dmaengine: ti: k3-udma: Add missing locking

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

dmaengine: ti: k3-udma: Add missing locking

Recent kernels complain about a missing lock in k3-udma.c when the lock

validator is enabled:

[ 4.128073] WARNING: CPU: 0 PID: 746 at drivers/dma/ti/../virt-dma.h:169 udma_start.isra.0+0x34/0x238

[ 4.137352] CPU: 0 UID: 0 PID: 746 Comm: kworker/0:3 Not tainted 6.12.9-arm64 #28

[ 4.144867] Hardware name: pp-v12 (DT)

[ 4.148648] Workqueue: events udma_check_tx_completion

[ 4.153841] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)

[ 4.160834] pc : udma_start.isra.0+0x34/0x238

[ 4.165227] lr : udma_start.isra.0+0x30/0x238

[ 4.169618] sp : ffffffc083cabcf0

[ 4.172963] x29: ffffffc083cabcf0 x28: 0000000000000000 x27: ffffff800001b005

[ 4.180167] x26: ffffffc0812f0000 x25: 0000000000000000 x24: 0000000000000000

[ 4.187370] x23: 0000000000000001 x22: 00000000e21eabe9 x21: ffffff8000fa0670

[ 4.194571] x20: ffffff8001b6bf00 x19: ffffff8000fa0430 x18: ffffffc083b95030

[ 4.201773] x17: 0000000000000000 x16: 00000000f0000000 x15: 0000000000000048

[ 4.208976] x14: 0000000000000048 x13: 0000000000000000 x12: 0000000000000001

[ 4.216179] x11: ffffffc08151a240 x10: 0000000000003ea1 x9 : ffffffc08046ab68

[ 4.223381] x8 : ffffffc083cabac0 x7 : ffffffc081df3718 x6 : 0000000000029fc8

[ 4.230583] x5 : ffffffc0817ee6d8 x4 : 0000000000000bc0 x3 : 0000000000000000

[ 4.237784] x2 : 0000000000000000 x1 : 00000000001fffff x0 : 0000000000000000

[ 4.244986] Call trace:

[ 4.247463] udma_start.isra.0+0x34/0x238

[ 4.251509] udma_check_tx_completion+0xd0/0xdc

[ 4.256076] process_one_work+0x244/0x3fc

[ 4.260129] process_scheduled_works+0x6c/0x74

[ 4.264610] worker_thread+0x150/0x1dc

[ 4.268398] kthread+0xd8/0xe8

[ 4.271492] ret_from_fork+0x10/0x20

[ 4.275107] irq event stamp: 220

[ 4.278363] hardirqs last enabled at (219): [<ffffffc080a27c7c>] _raw_spin_unlock_irq+0x38/0x50

[ 4.287183] hardirqs last disabled at (220): [<ffffffc080a1c154>] el1_dbg+0x24/0x50

[ 4.294879] softirqs last enabled at (182): [<ffffffc080037e68>] handle_softirqs+0x1c0/0x3cc

[ 4.303437] softirqs last disabled at (177): [<ffffffc080010170>] __do_softirq+0x1c/0x28

[ 4.311559] ---[ end trace 0000000000000000 ]---

This commit adds the missing locking.