powerpc/booke64: set RI in default MSR

commit 5266e58d upstream.

Set RI in the default kernel's MSR so that the architected way of
detecting unrecoverable machine check interrupts has a chance to work.
This is inline with the MSR setup of the rest of booke powerpc
architectures configured here.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>