amd-xgbe: Remove unnecessary include

The include of asm/cputype.h breaks the powerpc build. This
include was accidentally left in from driver debugging and
can be removed.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>,
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>