dma-fence: correct kernel-doc function parameter @flags

dma-fence: correct kernel-doc function parameter @flags

'make htmldocs' complains that dma_fence_unlock_irqrestore() is missing
a description of its @flags parameter. The description is there but it is
missing a ':' sign. Add that and correct the possessive form of "its".

WARNING: ../include/linux/dma-fence.h:414 function parameter 'flags' not described in 'dma_fence_unlock_irqrestore'

Fixes: 3e5067931b5d ("dma-buf: abstract fence locking v2")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20260407043649.2015894-1-rdunlap@infradead.org
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>