alpha: cleanup cpu type name composition

alpha: cleanup cpu type name composition

Introduce ALPHA_CPU_TYPE_NAME macro to replace rather ununique
TYPE macro that alpha uses. With new macro it will follow
the same naming convention as other targets.

While at it put scattered TypeInfo into one array which places
type desriptions at one place and reduces code a bit.

Signed-off-by: Igor Mammedov <[email protected]>
Acked-by: Richard Henderson <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <1507211474[email protected]>
Signed-off-by: Eduardo Habkost <[email protected]>