Document and enable the linux_spi driver

The linux_spi driver is now enabled by default on Linux.
A man page entry and a line in --list-supported output have been added.

Corresponding to flashrom svn r1498.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
3 files changed