kernel test robot reported kernel-doc warning for rm_host_ipi_action():

   arch/powerpc/kvm/book3s_hv_rm_xics.c:887: warning: This comment starts with '/**', but isn't a kernel-doc comment.
    * Host Operations poked by RM KVM

Since the function is static, remove the extraneous (second) asterisk at
the head of function comment.

Fixes: 0c2a6606 ("KVM: PPC: Book3S HV: Host side kick VCPU when poked by real-mode KVM")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/linux-doc/202204252334.Cd2IsiII-lkp@intel.com/
Link: https://lore.kernel.org/r/20220506070747.16309-1-bagasdotme@gmail.com