[stm32x] Use modern header include paths.

Replace includes of stm32/YY/xxxx.h with stm32/xxxx.h
Replace stm32/YY/nvic.h with cm3/nvic.h.
In some cases, the include list was resorted alphabetically when it was
complicated and I was reviewing them manually, but most of this was
automatically done.

examples/stm32/f1/stm32-maple/miniblink/miniblink.c

@@ -17,8 +17,8 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <libopencm3/stm32/f1/rcc.h>
-#include <libopencm3/stm32/f1/gpio.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
 
 static void gpio_setup(void)
 {

examples/stm32/f1/stm32-maple/usart/usart.c

@@ -17,8 +17,8 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <libopencm3/stm32/f1/rcc.h>
-#include <libopencm3/stm32/f1/gpio.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
 #include <libopencm3/stm32/usart.h>
 
 static void clock_setup(void)

examples/stm32/f1/stm32-maple/usart_irq/usart_irq.c

@@ -17,8 +17,8 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <libopencm3/stm32/f1/rcc.h>
-#include <libopencm3/stm32/f1/gpio.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
 #include <libopencm3/stm32/usart.h>
 #include <libopencm3/cm3/nvic.h>
 #include <libopencm3/cm3/scb.h>

examples/stm32/f1/stm32-maple/usb_cdcacm/cdcacm.c

@@ -18,8 +18,8 @@
  */
 
 #include <stdlib.h>
-#include <libopencm3/stm32/f1/rcc.h>
-#include <libopencm3/stm32/f1/gpio.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
 #include <libopencm3/usb/usbd.h>
 #include <libopencm3/usb/cdc.h>
 #include <libopencm3/cm3/scb.h>