i965: Add flag telling if miptree is for client consumption

i965: Add flag telling if miptree is for client consumption

Consider later on adding specific disable flags such as

MIPTREE_LAYOUT_DISABLE_AUX_MCS   = 1 << 3, /* CCS_D */
MIPTREE_LAYOUT_DISABLE_AUX_CCS_E = 1 << 4,
MIPTREE_LAYOUT_DISABLE_AUX       = MIPTREE_LAYOUT_DISABLE_AUX_MCS |
                                   MIPTREE_LAYOUT_DISABLE_AUX_CCS_E,

and equivalent boolean/enums into miptree.

Signed-off-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>