[coreboot] [PATCH] flashrom: Simplify ich_spi_write

[FENG Yu Ning]

Simlifies ich_spi_write, and changes the naming of "page" to "block".

Only write operation is modified. If this is proved to be acceptable,
read operation will be modified in a same manner later. Impact of
modification have been made minimal, other parts of flashrom should
not be affected.

Not tested due to lack of facilities. Appreciated if anyone could help testing.

Signed-off-by: FENG yu ning