staging: rtl8723bs: core: remove set but not used 'algthm'

staging: rtl8723bs: core: remove set but not used 'algthm'

Fix the following gcc warning:

drivers/staging/rtl8723bs/core/rtw_mlme_ext.c:1087:33: warning: variable
‘algthm’ set but not used [-Wunused-but-set-variable]
  unsigned int seq, len, status, algthm, offset;
                                 ^~~~~~

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20200427032342.27211-5-yanaijie@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>