ARM: stm32f0: fix syscfg mapping to fix EXTI config

The exticrX registers were shifted by a word, so configuring
an EXTI line on a port different of PA misconfigured the EXTI line
source and could flood with unwanted events.

Signed-off-by: Neil Armstrong <[email protected]>

Author: superna9999

arch/arm/soc/st_stm32/stm32f0/gpio_registers.h

@@ -66,6 +66,7 @@ union syscfg__exticr {
 
 struct stm32f0x_syscfg {
 	union syscfg_cfgr1 cfgr1;
+	u32_t rsvd;
 	union syscfg__exticr exticr1;
 	union syscfg__exticr exticr2;
 	union syscfg__exticr exticr3;