fsi: master-hub: Fix sparse warnings

fsi-master-hub.c:128:13: warning: incorrect type in assignment (different base types)
fsi-master-hub.c:128:13:    expected unsigned int [unsigned] [usertype] cmd
fsi-master-hub.c:128:13:    got restricted __be32 [usertype] <noident>
fsi-master-hub.c:208:13: warning: incorrect type in assignment (different base types)
fsi-master-hub.c:208:13:    expected restricted __be32 [addressable] [assigned] [usertype] reg
fsi-master-hub.c:208:13:    got int

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>