Host AP driver has code to support writing firmware to non-volatile
memory, a.k.a. flash.  This code has been extensively tested when Host
AP was a standalone driver.

Add a configuration option to the kernel to allow enabling this
functionality.  Improve the description of the RAM download option.
Mention cards that require it.  Remove obsolete scary comment.
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>