driconf: bump the maximum string size from 25 to 1024

The soon-to-be-introduced string entries will potentially introduce
very long strings that should not be truncated.

Reviewed-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Martin peres <martin.peres@linux.intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7212>
diff --git a/src/util/xmlconfig.h b/src/util/xmlconfig.h
index d7c43d4..130de09 100644
--- a/src/util/xmlconfig.h
+++ b/src/util/xmlconfig.h
@@ -39,7 +39,7 @@
 extern "C" {
 #endif
 
-#define STRING_CONF_MAXLEN 25
+#define STRING_CONF_MAXLEN 1024
 
 /** \brief Option data types */
 typedef enum driOptionType {