Replace the allocation code with the i915 version. This simplifies the
code a little, and importantly we get the accounting at the mgr level,
which is useful for debug (and maybe userspace), plus per resource
tracking so we can easily check if a resource is using one or pages in
the mappable part of vram (useful for eviction), or if the resource is
completely within the mappable portion (useful for checking if the
resource can be safely CPU mapped).

v2: Fix missing PAGE_SHIFT
v3: (Gwan-gyeong Mun)
  - Fix incorrect usage of ilog2(mm.chunk_size).
  - Fix calculation when checking for impossible allocation sizes, also
    check much earlier.
v4: (Gwan-gyeong Mun)
  - Fix calculation when extending the [fpfn, lpfn] range due to the
    roundup_pow_of_two().
v5: (Gwan-gyeong Mun)
  - Move the check for running out of mappable VRAM to before doing any of
    the roundup_pow_of_two().
v6: (Jani)
  - Stop abusing BUG_ON(). We can easily just use WARN_ON() here and
    return a proper error to the caller, which is much nicer if we ever
    trigger these.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>