glsl_compiler: Remove unused extra argument to printf in usage_fail

glsl_compiler: Remove unused extra argument to printf in usage_fail

Flagged by Oracle's parfait static analyzer:

Error: Format string argument mismatch (CWE 628)
   In call to printf with format string "usage: %s [options] <file.vert | file.geom | file.frag>\n\nPossible options are:\n"
      Too many arguments for format string (got more than 1 arguments)
        at line 285 of src/glsl/main.cpp in function 'usage_fail'.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>