MSM8976 does not have rpm clock named mmssnoc,
instead it's called sysmmnoc, drop define and reuse.
While we are at it add XO clock to list.

Fixes: 7d61e773 ("clk: qcom: smd: Add support for MSM8976 rpm clocks")
Signed-off-by: Adam Skladowski <a39.skl@gmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220426090226.27293-1-a39.skl@gmail.com