all: unmark experimental features

It's been some time now we've had those features, so unmark them
being experimental.

It does not mean everything is perfect, but may gather some more
testing of those features.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

# Alpha specific configuration file

## select ARCH_SUPPORTS_32

## select ARCH_DEFAULT_32

## select ARCH_USE_MMU

## select ARCH_SUPPORTS_WITH_CPU

## select ARCH_SUPPORTS_WITH_TUNE

##

## help The Alpha architecture.