drm/xe: Use vmalloc for array of bind allocation in bind IOCTL

Use vmalloc in effort to allow a user pass in a large number of binds in
an IOCTL (mesa use case). Also use array allocations rather open coding
the size calculation.

v2: Use __GFP_ACCOUNT for allocations (Thomas)

Fixes: dd08ebf6

 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240226155554.103384-1-matthew.brost@intel.com