arm64: dts: qcom: msm8998-mtp: Add alias for blsp1_uart3

arm64: dts: qcom: msm8998-mtp: Add alias for blsp1_uart3

The msm_serial driver has a predefined set of uart ports defined, which
is allocated either by reading aliases or if no match is found a simple
counter, starting at index 0. But there's no logic in place to prevent
these two allocation mechanism from colliding. As a result either none
or all of the active msm_serial instances must be listed as aliases.

Define blsp1_uart3 as "serial1" to mitigate this problem.

Fixes: 4cffb9f2c700 ("arm64: dts: qcom: msm8998-mtp: Enable bluetooth")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Link: https://lore.kernel.org/r/20191119011823.379100-1-bjorn.andersson@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>