amdgpu: move asic id table to a separate file

v2: fix an off by one error and leading white spaces
v3: use thread safe strtok_r(); initialize len before calling getline();
    change printf() to drmMsg(); add initial amdgpu.ids
v4: integrate some recent internal changes, including format changes
v5: fix line number for empty/commented lines; realloc to save memory;
    indentation changes
v6: remove a line error
v7: [Michel Dänzer]
* Move amdgpu.ids to new data directory
* Remove placeholder entries from amdgpu.ids
* Set libdrmdatadir variable in configure.ac instead of Makefile.am
  [Emil Velikov]
* Use isblank() instead of open-coding it [Emil Velikov]
* Don't leak asic_id_table memory if realloc fails [Emil Velikov]
* Check and bump table_max_size at the beginning of the while loop [Emil
  Velikov]
* Initialize table_max_size to the number of entries in data/amdgpu.ids
v8: [Michel Dänzer]
* Make sure amdgpu_asic_id.c gets rebuilt when amdgpu.ids changes

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Samuel Li <Samuel.Li@amd.com>