staging: rtl8723bs: remove all branchings between 2.4Ghz and 5Ghz band types

staging: rtl8723bs: remove all branchings between 2.4Ghz and 5Ghz band types

remove all code branchings tied to dual band support. The device
works only on 2.4Ghz band so there's no need to check which
band we are on. Removed all code branches that would be valid
only for 5Ghz for it's dead code. Removed enums, table fields
indexing by band type, function arguments passing current
band type and all other thing related to telling us
which band we are on.

Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/72bb27f6a7b3be607f93f5b406d863dd08376986.1624367071.git.fabioaiuto83@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>