ENGR00223349-1 gpmi: add a new field for HW_GPMI_TIMING1

ENGR00223349-1 gpmi: add a new field for HW_GPMI_TIMING1

The gpmi_nfc_compute_hardware_timing{} should contains all the
fields setting for gpmi timing registers. It already contains the fields
for HW_GPMI_TIMING0 and HW_GPMI_CTRL1.

So it is better to add a new field setting for HW_GPMI_TIMING1 in
this data structure. This makes the code more clear in logic.

This patch also changs some comments to make the code more readable.

Signed-off-by: Huang Shijie <b32955@freescale.com>