ARM: dts: msm: Enable UART for sdm660

BLSP2 UART1 is used as transport for Bluetooth between sdm660 & wcn3990.
Enable it so that Bluetooth can be enabled on sdm660 CDP/MTP/QRD.

Change-Id: Ib5102a96d42213bbeb230f83806b10a397353df8
Signed-off-by: Rupesh Tatiya <rtatiya@codeaurora.org>