stm32mon: Add support for STM32F412

BRANCH=none
BUG=b:38506987
TEST=On eve, where some sectors were locked, was able to unlock them:
- Enter bootloader:
st_flash --board=eve --enter_bootloader=true
- Unlock all pages:
/tmp/stm32mon -a 8 -l 0x8c -u
ChipID 0x441 : STM32F412
Bootloader v1.2, commands : \
00 01 02 11 21 31 44 63 73 82 92 32 45 64 74 83 93 00
Flash write unprotected.

Change-Id: I423e4b7f235ee2c9dddf28f4166fca2a74132733
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/511886
Reviewed-by: Alexandru M Stan <amstan@chromium.org>

util/stm32mon.c

@@ -84,6 +84,7 @@ struct stm32_def {
 	{0x432, "STM32F37xx",    0x40000,  2048, {13, 13} },
 	{0x442, "STM32F09x",     0x40000,  2048, {13, 13} },
 	{0x431, "STM32F411",     0x80000, 16384, {13, 19} },
+	{0x441, "STM32F412",     0x80000, 16384, {13, 19} },
 	{ 0 }
 };