We get 1 warning when building kernel with W=1:
drivers/net/phy/microchip.c:58:5: warning: no previous prototype for 'lan88xx_suspend' [-Wmissing-prototypes]

In fact, this function is only used in the file in which it is
declared and don't need a declaration, but can be made static.
so this patch marks this function with 'static'.
Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>