clk: samsung: clk-pll: Implement pll0818x PLL type

clk: samsung: clk-pll: Implement pll0818x PLL type

pll0818x PLL is used in Exynos850 SoC for CMU_G3D PLL. Operation-wise,
pll0818x is the same as pll0822x. The only difference is:
  - pl0822x is integer PLL with Middle FVCO (950 to 2400 MHz)
  - pl0818x is integer PLL with Low FVCO (600 to 1200 MHz)

Add pll0818x type as an alias to pll0822x.

Reviewed-by: Chanho Park <chanho61.park@samsung.com>
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20230223042133.26551-4-semen.protsenko@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>