dts: stm32wba: Fix RNG base address

Set RNG address to its non-secure alias.
See RM0493 STM32WBA5 Reference manual for details.
Using the secure alias (0x5..)instead of the non-secure alias (0x4..)
for this peripheral results in a SecureFault during kernel init if
TrustZone is activated, Zephyr is running as NSPE and RNG is
enabled.

Signed-off-by: Louis Feller <louis.feller@st.com>