gallium/radeon: increase the size of the renderer string
gallium/radeon: increase the size of the renderer string

Mine is longer than 64 bytes.

Reviewed-by: Nicolai Hähnle <0d0be6cf5ad662651be2dc5dfd44aa2b09d4c1cc@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler