stm32: rcc: fix missing ahb_frequency struct

Original commits, while appearing clean and tidy, hadn't even been
compile tested.  Trust no-one. Not even Scully.

Fixes: 770878e7b4
Fixes: 86d20ef00c
Fixes: 05ff0df322

include/libopencm3/stm32/f3/rcc.h

@@ -425,6 +425,7 @@ struct rcc_clock_scale {
 	uint8_t ppre1;
 	uint8_t ppre2;
 	uint8_t power_save;
+	uint32_t ahb_frequency;
 	uint32_t apb1_frequency;
 	uint32_t apb2_frequency;
 };

include/libopencm3/stm32/f4/rcc.h

@@ -564,6 +564,7 @@ struct rcc_clock_scale {
 	uint8_t ppre1;
 	uint8_t ppre2;
 	uint8_t power_save;
+	uint32_t ahb_frequency;
 	uint32_t apb1_frequency;
 	uint32_t apb2_frequency;
 };

include/libopencm3/stm32/l1/rcc.h

@@ -397,6 +397,7 @@ struct rcc_clock_scale {
 	uint8_t ppre1;
 	uint8_t ppre2;
 	enum pwr_vos_scale voltage_scale;
+	uint32_t ahb_frequency;
 	uint32_t apb1_frequency;
 	uint32_t apb2_frequency;
 	uint8_t msi_range;