mtd: cfi_cmdset_0001: Fix problem with unlocking timeout

mtd: cfi_cmdset_0001: Fix problem with unlocking timeout

Unlocking may take up to 1.4 seconds on some Intel flashes. So
lets use a max. of 1.5 seconds (1500ms) as timeout.

See "Clear Block Lock-Bits Time" on page 40 in
"3 Volt Intel StrataFlash Memory" 28F128J3,28F640J3,28F320J3 manual
from February 2003

This patch also fixes some other problems with this timeout:

- Don't use HZ in timeout "calculation"!
  While testing we noticed that an unlocking timeout occured with
  HZ=1000 and didn't occur with HZ=300. This was because the
  timeout parameter was calculated differently depending on the
  HZ value. Now a fixed value of 1500ms is used.

- The last parameter of WAIT_TIMEOUT (defined to
  inval_cache_and_wait_for_operation) has to be passed in
  micro-seconds. So multiply the ms value with 1000 and not 100
  to calculate this value.

- Use variable name "mdelay" instead of misleading "udelay".

Signed-off-by: Stefan Roese <sr@denx.de>
Tested-by: Stephan Gatzka <stephan@gatzka.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>