ethernet: fix up ps3_gelic_net.c for "ethernet: use eth_hw_addr_set()"

Another case needing a u8 * cast.

Fixes: a96d317f

 ("ethernet: use eth_hw_addr_set()")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/r/20211006122315.4e04fb87@canb.auug.org.au


Signed-off-by: Jakub Kicinski <kuba@kernel.org>