[RESEND^2] ssb: mark ssb_bus_register as __maybe_unused

[Kalle Valo]

> The SoC variant of the ssb code is now optional like the other
> ones, which means we can build the framwork without any
> front-end, but that results in a warning:
> 
> drivers/ssb/main.c:616:12: warning: 'ssb_bus_register' defined but not used [-Wunused-function]
> 
> This annotates the ssb_bus_register function as __maybe_unused to
> shut up the warning. A configuration like this will not work on
> any hardware of course, but we still want this to silently build
> without warnings if the configuration is allowed in the first
> place.
> 
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>
> Fixes: 845da6e58e19 ("ssb: add Kconfig entry for compiling SoC related code")
> Acked-by: Michael Buesch <m at bues.ch>

Thanks, applied to wireless-drivers.git.

Kalle Valo