intel/tools: fix possible memory leak in the error path

Found by Coverity.

Signed-off-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6667>

src/intel/tools/i965_disasm.c

@@ -103,6 +103,7 @@ i965_disasm_read_binary(FILE *fp, size_t *end)
 
    size = fread(assembly, *end, 1, fp);
    if (!size) {
+      free(assembly);
       return NULL;
    }
    return assembly;