brcmfmac: remove unnecessary call to brcmf_sdiod_set_backplane_window()

All functions that might require the window address changing call
brcmf_sdiod_set_backplane_window() prior to access. Thus resetting
the window is not required.

Signed-off-by: Ian Molton <ian@mnementh.co.uk>
[arend: corrected the driver prefix in the subject]
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>