KVM: PPC: Book3s HV: Remove unused function kvmppc_bad_interrupt

The commit fae5c9f3 ("KVM: PPC: Book3S HV: remove ISA v3.0 and v3.1
support from P7/8 path") removed the last reference to the function.

Fixes: fae5c9f3 ("KVM: PPC: Book3S HV: remove ISA v3.0 and v3.1 support from P7/8 path")
Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220711223617.63625-3-muriloo@linux.ibm.com