dma-buf/dma-resv.c: fix a typo

The dma_resv_wait_timeout() function return a value greater than zero
on success.

Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230416143849.1142779-1-suijingfeng@loongson.cn