drm/xe: Move VM dma-resv lock from xe_exec_queue_create to __xe_exec_queue_init

drm/xe: Move VM dma-resv lock from xe_exec_queue_create to __xe_exec_queue_init

The critical section which requires the VM dma-resv is the call
xe_lrc_create in __xe_exec_queue_init. Move this lock to
__xe_exec_queue_init holding it just around xe_lrc_create. Not only is
good practice, this also fixes a locking double of the VM dma-resv in
the error paths of __xe_exec_queue_init as xe_lrc_put tries to acquire
this too resulting in a deadlock.

Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: Maarten Lankhorst <[email protected]>
Signed-off-by: Matthew Brost <[email protected]>
Reviewed-by: Maarten Lankhorst <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]