marvell: mark mvneta and mvpp2 32-bit only

marvell: mark mvneta and mvpp2 32-bit only

Both of these drivers won't work on 64-bit architectures unless they
are redesigned, since they store a virtual address pointer in a 32-bit
field of the descriptors:

drivers/net/ethernet/marvell/mvneta_bm.c: In function 'mvneta_bm_construct':
drivers/net/ethernet/marvell/mvneta_bm.c:103:16: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
drivers/net/ethernet/marvell/mvpp2.c: In function 'mvpp2_prs_vlan_init':
drivers/net/ethernet/marvell/mvpp2.c:2563:32: error: large integer implicitly truncated to unsigned type [-Werror=overflow]

This limits the COMPILE_TEST option for the two drivers again to
only build them on 32-bit. This seems nicer than shutting up the
warnings, in case we ever actually want to use them on 64-bit,
as the warnings indicate which parts of the driver are currently
broken there.

Fixes: 920d4f791dc2 ("net: marvell: Allow drivers to be built with COMPILE_TEST")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>