Remove the dead kernel config option AEDSP16_MPU401.

Signed-off-by: Robert P. J. Day <mindspring.com>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>