i2c: pxa: Fix compile warning in 64bit mode

Fix below warning message, coming from 64 bit toolchain.

drivers/i2c/busses/i2c-pxa.c:1237:15:
warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]

Signed-off-by: Yipeng Yao <ypyao@marvell.com>
[vaibhav.hiremath@linaro.org: Updated Changelog]
Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Cc: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>