Documentation, arch: Remove leftovers from raw device

Raw device interface was removed so remove all references to configs
related to it.

Fixes: 603e4922 ("remove the raw driver")
Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Acked-by: Arnd Bergmann <arnd@arndb.de> [arch/arm/configs]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>