tty: serial: jsm: fix two assignments in if conditions

Fixes two warnings reported of the form
"ERROR: do not use assignment in if condition"
reported by checkpatch.pl.

Signed-off-by: Alexander Vorwerk <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/jsm/jsm_neo.c

···
 	ch->ch_cached_lsr = 0;
 
 	/* Store how much space we have left in the queue */
-	if ((qleft = tail - head - 1) < 0)
+	qleft = tail - head - 1;
+	if (qleft < 0)
 		qleft += RQUEUEMASK + 1;
 
 	/*

drivers/tty/serial/jsm/jsm_tty.c

···
 	int qleft;
 
 	/* Store how much space we have left in the queue */
-	if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
+	qleft = ch->ch_r_tail - ch->ch_r_head - 1;
+	if (qleft < 0)
 		qleft += RQUEUEMASK + 1;
 
 	/*