input: Fix i8042 keyboard reset

The i8042 keyboard reset was not checking the results of the output
buffer after the reset command. This can jam up some KBC/keyboards.
Also, remove a write to the wrong register and the CONFIG setting
around the incorrect write.

Signed-off-by: Marc Jones <marc.jones@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@ti.com>