fix(st-regulator): use Boolean type for tests

This corrects MISRA C2012-14.4
The controlling expression of an if statement and the controlling
expression of an iteration-statement shall have essentially Boolean type.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: Iacc58349cc3ab558fb4ffe0605a623e84e21e035
1 file changed