Remove FreeBSD-specific PAM configuration

Something in FreeBSD's PAM modules changed, and
now using the "passwd" configuration file fails to unlock

meson.build

@@ -152,19 +152,10 @@ executable('swaylock',
 	install: true
 )
 
-if is_freebsd
 install_data(
-		'pam/swaylock.freebsd',
-		install_dir: sysconfdir + '/pam.d/',
-		rename: 'swaylock'
+	'pam/swaylock',
+	install_dir: sysconfdir + '/pam.d/'
 )
-else
-	install_data(
-		'pam/swaylock.linux',
-		install_dir: sysconfdir + '/pam.d/',
-		rename: 'swaylock'
-	)
-endif
 
 if scdoc.found()
 	sh = find_program('sh')

pam/swaylock.freebsd

@@ -1,6 +0,0 @@
-#
-# PAM configuration file for the swaylock screen locker. By default, it includes
-# the 'passwd' configuration file (see /etc/pam.d/passwd)
-#
-
-auth include passwd