File README.updates of Package Mesa-drivers.25780

DRI Driver update mechanism
---------------------------

If any corresponding DRI driver is found in "/usr/lib/dri/updates/"
it will be favored over the one in "/usr/lib/dri/" and will be used
for 32/64 bit applications.

On 32/64 bit biarch platforms additionally a corresponding DRI driver
in "/usr/lib64/dri/updates/" will be favored over the one in 
"/usr/lib64/dri/" and will be used for 64bit applications.