fix(st-clock): do not reconfigure LSE

If LSE oscillator is already ON, which is the case when returning from
low-power state or if we are on VBAT, it mustn't be reconfigured.

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Change-Id: Ie75f2b0b42aeb3d95e2266e1fca811a2f2b3e29f
2 files changed