stm32mon: add STM32H7 identifier

Add a new chip ID to support the STM32H7x3 parts.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BRANCH=none
BUG=b:67081508
TEST=flash_ec --board=meowth_fp

Change-Id: I3897a74f5414e0e6b13890291706134c2d916af9
Reviewed-on: https://chromium-review.googlesource.com/856977
Commit-Ready: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>

util/stm32mon.c

@@ -93,6 +93,7 @@ struct stm32_def {
 	{0x442, "STM32F09x",     0x40000,  2048, {13, 13} },
 	{0x431, "STM32F411",     0x80000, 16384, {13, 19} },
 	{0x441, "STM32F412",     0x80000, 16384, {13, 19} },
+	{0x450, "STM32H74x",    0x200000, 131768, {13, 19} },
 	{0x451, "STM32F76x",    0x200000, 32768, {13, 19} },
 	{ 0 }
 };