iceprog: Better reset of flash
iceprog: Better reset of flash

If the flash was in a 'weird' mode (like CRM, QPI, ...), sending
a continuous stream of 0xff should take it out of it.

It looks like the previous code was trying to do that, but
was only transferring 8 bits and then 2 bits which is way
too short.

Signed-off-by: Sylvain Munaut <349f318521b45672c77207abf1a5ed60eb011db1@246tNt.com>

SymbiFlow/icestorm,SymbiFlow/icestorm,SymbiFlow/icestorm,SymbiFlow/icestorm