Fix various typos

Found via codespell v2.1.dev0
`codespell -q 3 -L ans,filp,fils,hsi`

Update nl80211.h

Update wgd.sh

Update update_sdcard.sh

Update slice_cfg.sh

Update side_ch_ctl.c

Update set_csma_normal.sh

Update set_csma_high.sh

Update set_ant.sh

Update version.sh

Update sections.c

Update sdrctl.h

Update sdrctl.c

Update nl80211_testmode_def.h

Update cmd.c

Update sdr-ad-hoc-up.sh

Update sdr-ad-hoc-join.sh

Update sdcard_boot_update.sh

Update rf_init.sh

Update prepare_kernel.sh

Update post_config.sh

Update nic_back_to_normal.sh

Update monitor_ch.sh

Update link_perf_test.sh

Update inject_80211.sh