libmemtrack: Fix the kgsl memory flag to determine usermapped buffers

The flag is the last character in 'flags' field array. It was wrongly
indexed at flags[6] causing all entries to be marked as unaccounted.
The correct check should be for flags[5] to be equal to 'Y'.

Change-Id: I9f9af884b697363186d6315e5fb7c5673c22a495
1 file changed