ARC: mm: arc700: Don't assume 2 colours for aliasing VIPT dcache

ARC: mm: arc700: Don't assume 2 colours for aliasing VIPT dcache

commit 08fe007968b2b45e831daf74899f79a54d73f773 upstream.

An ARC700 customer reported linux boot crashes when upgrading to bigger
L1 dcache (64K from 32K). Turns out they had an aliasing VIPT config and
current code only assumed 2 colours, while theirs had 4. So default to 4
colours and complain if there are fewer. Ideally this needs to be a
Kconfig option, but heck that's too much of hassle for a single user.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>