r300g: Check return value of snprintf().

Would have at least prevented the crash the previous patch fixed.

Cc: 10.4, 10.5 <mesa-stable@lists.freedesktop.org>
Bugzilla: https://bugs.gentoo.org/show_bug.cgi?id=540970
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
1 file changed