KVM: PPC: Book3S HV: Check return value of kvmppc_radix_init

The return of the function is being shadowed by the call to
kvmppc_uvmem_init.

Fixes: ca9f4942

 ("KVM: PPC: Book3S HV: Support for running secure guests")
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220125155735.1018683-2-farosas@linux.ibm.com