w1: mxc_w1: Optimize mxc_w1_ds2_touch_bit()
w1: mxc_w1: Optimize mxc_w1_ds2_touch_bit()

According to the i.MX reference manual, the read/write bit operations
takes from 60 us to 120 us.
This patch optimizes mxc_w1_ds2_touch_bit() function to use proper
value for such delay. Nevertheless, a small margin for the timeout has
been added for the case if clock frequency is inaccurate.

Signed-off-by: Alexander Shiyan <2d24902f83da69c248f5b0282406fefa25814305@mail.ru>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs