msm_serial_hs_lite : Handle -EPROBE_DEFER with clk_get() API usage

Linux clock driver is moving with device tree based usage. It is not
necessary that when UART driver probe is called, before that Linux clock
driver would be initialized.
Hence this change handles -EPROBE_DEFER if clk_get() API returns that and
mark UART driver Probe as deffered probe.

Change-Id: I501ec48445053d9da147f132f0631e4511ca592f
Signed-off-by: Saket Saurabh <ssaurabh@codeaurora.org>