clk: msm: clock-gcc-8998: Update parent src for qup_spi/uart_apps clocks

The blsp qup_spi and uart_apps frequencies in the LOW_SVS corner needs
to be derived from the gpll0_div2 source, so as to not result in under
voting, so update the sources for the same.

Change-Id: I2ab9ced70db0fdf2c8c93bce48ff4e97ec36125a
Signed-off-by: Amit Nischal <anischal@codeaurora.org>