Fix i8042.c to ignore fake key releases generated by AT keyboard

in translated set 2. This fixes a problem where shift-pgup, with
the pgup released first generated an unknown scancode warning and
the shift remained stuck.

drivers/input/serio/i8042.c

@@ -54,6 +54,7 @@ static struct serio i8042_kbd_port;
 static struct serio i8042_aux_port;
 static unsigned char i8042_initial_ctr;
 static unsigned char i8042_ctr;
+static unsigned char i8042_last_e0;
 struct timer_list i8042_timer;
 
 #ifdef I8042_DEBUG_IO
@@ -366,12 +367,15 @@ static void i8042_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 					if (data > 0x7f) {
 						if (test_and_clear_bit(data & 0x7f, i8042_unxlate_seen)) {
 							serio_interrupt(&i8042_kbd_port, 0xf0, dfl);
+							if (i8042_last_e0 && (data == 0xaa || data == 0xb6))
+								set_bit(data & 0x7f, i8042_unxlate_seen);
 							data = i8042_unxlate_table[data & 0x7f];
 						}
 					} else {
 						set_bit(data, i8042_unxlate_seen);
 						data = i8042_unxlate_table[data];
 					}
+					i8042_last_e0 = (data == 0xe0);
 				}
 				serio_interrupt(&i8042_kbd_port, data, dfl);
 			}