unify len and addr type for memory/address APIs

unify len and addr type for memory/address APIs

Some address/memory APIs have different type between
'hwaddr/target_ulong addr' and 'int len'. It is very unsafe, especially
some APIs will be passed a non-int len by caller which might cause
overflow quietly.
Below is an potential overflow case:
    dma_memory_read(uint32_t len)
      -> dma_memory_rw(uint32_t len)
        -> dma_memory_rw_relaxed(uint32_t len)
          -> address_space_rw(int len) # len overflow

CC: Paolo Bonzini <[email protected]>
CC: Peter Crosthwaite <[email protected]>
CC: Richard Henderson <[email protected]>
CC: Peter Maydell <[email protected]>
CC: Stefano Garzarella <[email protected]>
Signed-off-by: Li Zhijian <[email protected]>
Reviewed-by: Peter Maydell <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Reviewed-by: Stefano Garzarella <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>