drm/xe: unconditionally apply PINNED for pin_map()

Some users apply PINNED and some don't when using pin_map(). The pin in
pin_map() should imply PINNED so just unconditionally apply it and clean
up all users.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Link: https://lore.kernel.org/r/20250403102440.266113-14-matthew.auld@intel.com