mips: cavium-octeon: clean up kernel-doc in cvmx-interrupt-decodes.c

Fix kernel-doc warnings reported by kernel test robot:

arch/mips/cavium-octeon/executive/cvmx-interrupt-decodes.c:49: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * __cvmx_interrupt_gmxx_rxx_int_en_enable enables all interrupt bits in cvmx_gmxx_rxx_int_en_t
   arch/mips/cavium-octeon/executive/cvmx-interrupt-decodes.c:230: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * __cvmx_interrupt_pcsx_intx_en_reg_enable enables all interrupt bits in cvmx_pcsx_intx_en_reg_t
   arch/mips/cavium-octeon/executive/cvmx-interrupt-decodes.c:271: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * __cvmx_interrupt_pcsxx_int_en_reg_enable enables all interrupt bits in cvmx_pcsxx_int_en_reg_t
   arch/mips/cavium-octeon/executive/cvmx-interrupt-decodes.c:301: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * __cvmx_interrupt_spxx_int_msk_enable enables all interrupt bits in cvmx_spxx_int_msk_t
   arch/mips/cavium-octeon/executive/cvmx-interrupt-decodes.c:340: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * __cvmx_interrupt_stxx_int_msk_enable enables all interrupt bits in cvmx_stxx_int_msk_t

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Aditya Srivastava <yashsri421@gmail.com>
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>