drivers: regulator: Fix -Wpointer-to-int-cast.

drivers/regulator/qpnp-lcdb-regulator.c:2734:18: warning: cast to smaller integer type 'u8' (aka 'unsigned char') from 'const void *' [-Wvoid-pointer-to-int-cast]
        lcdb->subtype = (u8)of_device_get_match_data(&pdev->dev);
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Change-Id: Ief3f187811f5a15c1c89037bc97896c0374415ef