ti-st: clean up data types (fix harmless memory corruption)

The big issue here is:

	of_property_read_u32(np, "flow_cntrl", (u32 *)&dt_pdata->flow_cntrl);

"->flow_cntrl" is a char so when we write a 32 bit number to it then it
corrupts past the end of the char.  It's probably hard to notice because
the struct has padding so the code works on little endian systems. But
on a big endian system the code would fail and on a 64 bit, big endian
systems then "nshutdown_gpio" and "baud_rate" would be buggy as well.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>