x11-drivers/xorgxrdp: Fix build with pkg 2.1.0

Fix suggested by bapt.

While here, reformat Makefile with portfmt, and pet portclippy.

PR: 285815
Reported by: Anton Saietskii
Sponsored by: Cybertrust Japan

(cherry picked from commit 687b2f44b3eff4d8d7579c78b48845a2ae69c99b)