soc: arm: stm32g4 add rtc feature on this serie

This patch enables the rtc clock on the stm32g4 soc
from STMicroelectronics.
Even if the set by default (reset value of theRCC_APB1ENR)
the bit is marked as 1.

Signed-off-by: Francois Ramu <francois.ramu@st.com>
2 files changed