softpipe: correct signature of get_compiler_options

This gets rid of a harmless but annoying compiler warning on MSVC.

Fixes: 73bafb5ee3 ("gallium: s/unsigned/enum pipe_shader_type/ for get_compiler_options()")
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7524>

src/gallium/drivers/softpipe/sp_screen.c

@@ -89,7 +89,8 @@ static const nir_shader_compiler_options sp_compiler_options = {
 
 static const void *
 softpipe_get_compiler_options(struct pipe_screen *pscreen,
-                              enum pipe_shader_ir ir, unsigned shader)
+                              enum pipe_shader_ir ir,
+                              enum pipe_shader_type shader)
 {
    assert(ir == PIPE_SHADER_IR_NIR);
    return &sp_compiler_options;