fix(st-clock): give the size for parent_mp13 and dividers_mp13 tables

This corrects MISRA C2012-9.5:
Where designated initializers are used to initialize an array object
the size of the array shall be specified explicitly.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I4c331b0225af975fd022ffe9e5fd1d536ed59879
1 file changed