b43: shut up clang -Wuninitialized variable warning

commit d825db34 upstream.

Clang warns about what is clearly a case of passing an uninitalized
variable into a static function:

drivers/net/wireless/broadcom/b43/phy_lp.c:1852:23: error: variable 'gains' is uninitialized when used here
      [-Werror,-Wuninitialized]
                lpphy_papd_cal(dev, gains, 0, 1, 30);
                                    ^~~~~
drivers/net/wireless/broadcom/b43/phy_lp.c:1838:2: note: variable 'gains' is declared here
        struct lpphy_tx_gains gains, oldgains;
        ^
1 error generated.

However, this function is empty, and its arguments are never evaluated,
so gcc in contrast does not warn here. Both compilers behave in a
reasonable way as far as I can tell, so we should change the code
to avoid the warning everywhere.

We could just eliminate the lpphy_papd_cal() function entirely,
given that it has had the TODO comment in it for 10 years now
and is rather unlikely to ever get done. I'm doing a simpler
change here, and just pass the 'oldgains' variable in that has
been initialized, based on the guess that this is what was
originally meant.

Fixes: 2c0d6100 ("b43: LP-PHY: Begin implementing calibration & software RFKILL support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>