rng: stm32: rename STM32 RNG driver

Rename the RNG driver as it is usable by other STM32 platforms
than the STM32MP1x ones. Rename CONFIG_RNG_STM32MP1 to
CONFIG_RNG_STM32

Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
Reviewed-by: Grzegorz Szymaszek <gszymaszek@short.pl>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
7 files changed