refactor(st-clock): update STGEN management

Rework STGEN config function, and move it to stm32mp_clkfunc.c file.

Change-Id: I7784a79c486d1b8811f6f8d123e49ea34899e9b6
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/include/drivers/st/stm32mp_clkfunc.h b/include/drivers/st/stm32mp_clkfunc.h
index 4876213..9df38d6 100644
--- a/include/drivers/st/stm32mp_clkfunc.h
+++ b/include/drivers/st/stm32mp_clkfunc.h
@@ -28,4 +28,9 @@
 int fdt_get_clock_id(int node);
 unsigned long fdt_get_uart_clock_freq(uintptr_t instance);
 
+void stm32mp_stgen_config(unsigned long rate);
+void stm32mp_stgen_restore_counter(unsigned long long value,
+				   unsigned long long offset_in_ms);
+unsigned long long stm32mp_stgen_get_counter(void);
+
 #endif /* STM32MP_CLKFUNC_H */