Boot: Update MCUboot url

MCUboot URL was changed from https://github.com/JuulLabs-OSS/mcuboot
to https://github.com/mcu-tools/mcuboot

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: If5e3d103ed420258046b7cf1071d36bf5e883476
diff --git a/bl2/ext/mcuboot/include/hal/hal_flash.h b/bl2/ext/mcuboot/include/hal/hal_flash.h
index dd3d206..4fbd158 100644
--- a/bl2/ext/mcuboot/include/hal/hal_flash.h
+++ b/bl2/ext/mcuboot/include/hal/hal_flash.h
@@ -19,7 +19,7 @@
 
 /*
  * Original code taken from mcuboot project at:
- * https://github.com/JuulLabs-OSS/mcuboot
+ * https://github.com/mcu-tools/mcuboot
  * Git SHA of the original version: 50d24a57516f558dac72bef634723b60c5cfb46b
  *
  * This file is only here for compatibility and build purposes, and was emptied