Make brcmf_sdio_regrw_helper() static removing its use outside of
the bcmsdh.c source file.
Reviewed-by: NFranky Lin <frankyl@broadcom.com>
Reviewed-by: NHante Meuleman <meuleman@broadcom.com>
Reviewed-by: NPieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>