aspeed/smc: Fix number of dummy cycles for FAST_READ_4 command

aspeed/smc: Fix number of dummy cycles for FAST_READ_4 command

The Linux kernel recently started using FAST_READ_4 commands.
This results in flash read failures. At the same time, the m25p80
emulation is seen to read 8 more bytes than expected. Adjusting the
expected number of dummy cycles to match FAST_READ fixes the problem.

Fixes: f95c4bffdc4c ("aspeed/smc: snoop SPI transfers to fake dummy cycles")
Reviewed-by: Cédric Le Goater <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Peter Maydell <[email protected]>