net: bcmgenet: Fix compile warning

bcmgenet_wol_resume() is only used in bcmgenet_resume(), which is only
defined when CONFIG_PM_SLEEP is enabled. This leads to the following
compile warning when building with !CONFIG_PM_SLEEP:

drivers/net/ethernet/broadcom/genet/bcmgenet.c:1967:12: warning: ‘bcmgenet_wol_resume’ defined but not used [-Wunused-function]

Since bcmgenet_resume() is the only user of bcmgenet_wol_resume(), fix
this by directly inlining the function there.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>