goldfish: pipe: fix warnings for 32bit builds

drivers/platform/goldfish/goldfish_pipe.c: In function 'goldfish_cmd_status':
drivers/platform/goldfish/goldfish_pipe.c:164:14: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     writel((u32)(u64)pipe, dev->base + PIPE_REG_CHANNEL);
                 ^
drivers/platform/goldfish/goldfish_pipe.c: In function 'goldfish_cmd':
drivers/platform/goldfish/goldfish_pipe.c:180:14: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     writel((u32)(u64)pipe, dev->base + PIPE_REG_CHANNEL);
                 ^
drivers/platform/goldfish/goldfish_pipe.c: In function 'goldfish_pipe_read_write':
drivers/platform/goldfish/goldfish_pipe.c:337:16: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
       writel((u32)(u64)pipe, dev->base + PIPE_REG_CHANNEL);

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Jun Tian <jun.j.tian@intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>