brcmfmac: Protect tx seq number for data and control

brcmfmac: Protect tx seq number for data and control

SDIO tx uses a sequence number which is common for data
and control. This requires that access to this sequence number
is protected. A mutex was used to achieve this, but it also
required the reordering of code for tx control.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>