Revert "Revert "mtd: rawnand: gpmi: Fix setting busy timeout setting""

This reverts commit 15a3adfe.

The backport of [1] relies on having [2] also backported. Having only
one of the two results in a bogus hw->timing1 setting.

If only [2] is backportet the 16 bit register value likely underflows
resulting in a busy_wait_timeout of 0.
Or if only [1] is applied the value likely overflows with chances of
having last 16 LSBs all 0 which would then result in a
busy_wait_timeout of 0 too.

Both cases may lead to NAND data corruption, e.g. on a Colibri iMX7
setup this has been seen.

[1] commit 0fddf9ad ("mtd: rawnand: gpmi: Set WAIT_FOR_READY timeout based on program/erase times")
[2] commit 06781a50

 ("mtd: rawnand: gpmi: Fix setting busy timeout setting")

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>