Runtime: clEnqueueMapImage also need to maintain the mapped images.
Runtime: clEnqueueMapImage also need to maintain the mapped images.

v3: Use cl_mem_unmap_gtt rather than cl_mem_unmap_auto in function _cl_map_mem.
v2: merge with:

commit 0237652c579123436e5f48514f733e36c8b5264a
Author: Yang Rong <78759e37dc7114caed18f74e7515c5cb519dbf6d@intel.com>
Date:   Fri Aug 23 11:04:21 2013 +0800

    Add clEnqueueMapBuffer and clEnqueueMapImage non-blocking map support.

Signed-off-by: Zhigang Gong <e04a7b9b70b1e4c6318cf117dcd1a9056e14b97a@linux.intel.com>
Revied-by: "Yang, Rong R" <78759e37dc7114caed18f74e7515c5cb519dbf6d@intel.com>

ignatenkobrain/beignet,ignatenkobrain/beignet,zhenyw/beignet,freedesktop-unofficial-mirror/beignet,freedesktop-unofficial-mirror/beignet,zhenyw/beignet,zhenyw/beignet,ignatenkobrain/beignet,wdv4758h/beignet,wdv4758h/beignet,freedesktop-unofficial-mirror/beignet,wdv4758h/beignet,zhenyw/beignet,ignatenkobrain/beignet,wdv4758h/beignet,freedesktop-unofficial-mirror/beignet,wdv4758h/beignet,ignatenkobrain/beignet,zhenyw/beignet