alpha: types: use <asm-generic/int-*.h> for the alpha architecture

This modifies <asm-alpha/types.h> to use the <asm-generic/int-*.h>
generic include files.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>