msm_serial_hs_lite: Increase TX path timeout

Increase the HSL TX path timeout to account for the fact
that the TX buffer size is specified in words rather than
bytes, and that some implementations may have a larger TX
queue size than what was assumed in the original timeout
calculation.

Change-Id: Ie459a2fcdd8a85c2e97ff3a87d60a9c30ce50ec3
CRs-Fixed: 359256
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>