xmlconfig: read more config files from drirc.d/

xmlconfig: read more config files from drirc.d/

Driver and application can put their drirc files in
${datadir}/drirc.d/ with name xxx.conf. Config files
will be read and applied in file name alphabetic order.

So there are three places for drirc listed in order:
1. /usr/share/drirc.d/
2. /etc/drirc
3. ~/.drirc

v4:
  fix meson build

v3:
  1. seperate driParseConfigFiles refine into another patch
  2. fix entries[i] mem leak

v2:
  drop /etc/drirc.d

Signed-off-by: Qiang Yu <Qiang.Yu@amd.com>
Acked-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>