This switches alpha to use drivers/Kconfig instead of including most of
files included by drivers/Kconfig, thus enabling previously omitted i2c
(already used in some drivers available on alpha) and telephony drivers.

Because drivers/message/fusion/Kconfig was included only conditionally
("if PCI"), this patch also changes CONFIG_FUSION to depend on PCI.

(these changes were consulted with Christoph Hellwig in "i2c on alpha
- used but not available in 2.6.3" thread on LKML)