powerpc: Remove KVMTEST from RELON exception handlers

KVMTEST is a macro which checks whether we are taking an exception from
guest context, if so we branch out of line and eventually call into the
KVM code to handle the switch.

When running real guests on bare metal (HV KVM) the hardware ensures
that we never take a relocation on exception when transitioning from
guest to host. For PR KVM we disable relocation on exceptions ourself in
kvmppc_core_init_vm(), as of commit a413f474

 "Disable relocation on
exceptions whenever PR KVM is active".

So convert all the RELON macros to use NOTEST, and drop the remaining
KVM_HANDLER() definitions we have for 0xe40 and 0xe80.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
CC: <stable@vger.kernel.org> [v3.9+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>