Input: i8042 - introduce a tougher reset

Some touchpads don't reset right the first time (MSI Wind U-100 for
example).  This patch will retry the reset up to 5 times.

In addition, on x86, we don't fail entire i8042 initialization if
controller reset fails in hope that keyboard port will still be
functional and user will still get a working keyboard. This is
especially important on netbooks.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>