staging: r8188eu: odm BoardType is never set

odm BoardType is never set, so it's always 0 (ODM_BOARD_NORMAL).
Remove dead code and the BoardType itself.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20211011201159.10252-8-martin@kaiser.cx


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>