fix(st-clock): initialize pllcfg table

The issue was found by Coverity:
CID 376582:    (UNINIT)
    Using uninitialized value "*pllcfg[_PLL4]" when calling
    "stm32mp1_check_pll_conf".
CID 376582:    (UNINIT)
    Using uninitialized value "*pllcfg[_PLL3]" when calling
    "stm32mp1_check_pll_conf".

Check PLL configs are valid before using pllcfg.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I49de849eaf451d0c165a8eb8555112a0a4140bbc
1 file changed