Fix ATMEL 29C020 detection with flashrom

The JEDEC probe routine had a delay of 10 us after entering ID mode
and this was insufficient for the 29C020. The data sheet claims we
have to wait 10 ms, but tests have shown that 20 us suffice. Allow for
variations in chip delays with a factor of 2 safety margin.

Corresponding to flashrom svn r159 and coreboot v2 svn r2962.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Peter Stuge <peter@stuge.se>
1 file changed