brcmfmac: Demote non-compliant kernel-doc headers

brcmfmac: Demote non-compliant kernel-doc headers

Fixes the following W=1 kernel build warning(s):

 drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c:2040: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:1295: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

Cc: Franky Lin <franky.lin@broadcom.com>
Cc: Hante Meuleman <hante.meuleman@broadcom.com>
Signed-off-by: Yang Shen <shenyang39@huawei.com>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210517050141.61488-5-shenyang39@huawei.com