[flashrom] [Patch] Add FEATURE_WRSR_WREN to feature_bits for many Eon SPI flash chips

[David Hendricks]

This patch adds the FEATURE_WRSR_WREN bit to the feature_bits for many of
the supported Eon chips. I was unable to find datasheets for all the similar
Eon chips... there seems to be some huge number of variants listed on
http://www.eonssi.com/products/products.aspx . Perhaps we can safely assume
they are sanely uniform and apply FEATURE_WRSR_WREN to all of them?

Signed-off-by: David Hendricks