iris: add Android build

Note that at least following additional libs/components require changes
since they refer to BOARD_GPU_DRIVERS variable which is used to select
the driver:

  - mixins
  - minigbm
  - libdrm
  - drm_gralloc

v2: (feedback by Gustaw Smolarczyk) Fix trailing \ in a few cases

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
7 files changed