mfd: tps65217: Naturalise cross-architecture discrepancies

If we compile the TPS65217 for a 64bit architecture we receive the following
warnings:

drivers/mfd/tps65217.c: In function ‘tps65217_probe’:
drivers/mfd/tps65217.c:173:13:
  warning: cast from pointer to integer of different size
   chip_id = (unsigned int)match->data;
             ^

Signed-off-by: Lee Jones <lee.jones@linaro.org>