KVM: PPC: Book3S HV: Remove virt mode checks from real mode handlers

Now that the P7/8 path no longer supports radix, real-mode handlers
do not need to deal with being called in virt mode.

This change effectively reverts commit acde2572 ("KVM: PPC: Book3S
HV: Add radix checks in real-mode hypercall handlers").

It removes a few more real-mode tests in rm hcall handlers, which
allows the indirect ops for the xive module to be removed from the
built-in xics rm handlers.

kvmppc_h_random is renamed to kvmppc_rm_h_random to be a bit more
descriptive and consistent with other rm handlers.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-25-npiggin@gmail.com