MLK-11239 ARM: dts: imx7d-sdb-touch: correct the format of u16 values

In tsc2046 touch driver, the values such as ti,x-min is defined as a u16
value. the driver use API of_property_read_u16() read the value. For these
u16 value, the dts entry should be like:
    property = /bits/ 16 <0x5000>;
This describe the property as a u16 value.

if the dts entry write like following:
	property = <0x5000>;
of subsystem will read this property as a u32 value in default. Due to the
DTB file is big-endian, and our memory system is little endian, this will
make the driver can't read the correct value.

This patch correct the format of u16 values, and set the default value defined
in tsc2046 touch driver.

Signed-off-by: Haibo Chen <haibo.chen@freescale.com>