[PATCH] bcm43xx: Add error checking in bcm43xx_sprom_write()

The Coverity checker noted that these "if (err)"'s couldn't ever be
true.

It seems the intention was to check the return values of the
bcm43xx_pci_write_config32()'s?

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>