net/hplance: hplance_init() should be __devinit

WARNING: vmlinux.o(.devinit.text+0x253e): Section mismatch in reference from the function hplance_init_one() to the function .init.text:hplance_init()

The forward declaration had the correct attribute, but the actual function
definition hadn't.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>