staging: octeon: convert cvmx_helper_interface_mode_t from typedef to plain enum

staging: octeon: convert cvmx_helper_interface_mode_t from typedef to plain enum

The Linux kernel coding style discourages the use of typedefs for
enums. Convert cvmx_helper_interface_mode_t to a plain 'enum
cvmx_helper_interface_mode' and update all users across the MIPS
Octeon architecture code and the staging driver stubs.

No functional change.

Signed-off-by: Eric Wu <kunjinkao.jp@gmail.com>
Link: https://patch.msgid.link/20260427155427.668540-3-kunjinkao.jp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>