[PATCH] epca iomem annotations + several missing readw()

[originally sent to Alan, he had no problems with it]

 - iomem pointers marked as such
 - several direct dereferencings of such pointers replaced with read[bw]().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>