embed/trezorhal: move lowlevel.{c,h} from boardloader to trezorhal

SConscript.boardloader

@@ -59,7 +59,6 @@ SOURCE_STMHAL = [
 
 SOURCE_BOARDLOADER = [
     'embed/boardloader/startup.s',
-    'embed/boardloader/lowlevel.c',
     'embed/boardloader/main.c',
 ]
 
@@ -67,6 +66,7 @@ SOURCE_TREZORHAL = [
     'embed/trezorhal/common.c',
     'embed/trezorhal/image.c',
     'embed/trezorhal/flash.c',
+    'embed/trezorhal/lowlevel.c',
     'embed/trezorhal/mini_printf.c',
     'embed/trezorhal/sdcard.c',
     'embed/trezorhal/stm32.c',

embed/trezorhal/lowlevel.h

@@ -17,8 +17,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef BOARDLOADER_LOWLEVEL_H
-#define BOARDLOADER_LOWLEVEL_H
+#ifndef __TREZORHAL_LOWLEVEL_H__
+#define __TREZORHAL_LOWLEVEL_H__
 
 #include "secbool.h"
 
@@ -31,4 +31,4 @@ secbool flash_configure_option_bytes(void);
 void periph_init(void);
 secbool reset_flags_check(void);
 
-#endif // BOARDLOADER_LOWLEVEL_H
+#endif // __TREZORHAL_LOWLEVEL_H__