ARM: dts: msm: Increase USB QMP PHY register address space size for MDM9640

Currently used USB QMP PHY register address space size is 0x45c which is
used by Linux USB QMP PHY driver to memory mapped the region. Some of
QMP PHY registers' read/write offset is above this size. Hence increase
USB QMP PHY register address space size to 0x750 to memory map complete
USB QMP PHY related register address space.

CRs-Fixed: 992231
Change-Id: Ic519c7c71fa4c1a91fa7784f2657c50b113e3222
Signed-off-by: Mayank Rana <mrana@codeaurora.org>