west.yml: MCUboot synchronization from upstream

Update Zephyr fork of MCUboot to revision:
  990b1fcb367e27056b282f183e819964fdbfe907

  - f76fba70 boot: bootutil: swap_scratch: Fix issue with bricking
    device
  - 7253f01c boot: bootutil: Refactor erase functionality to fix
    watchdog feeding
  - a98bff9f boot: zephyr: kconfig: Fix issues and re-order
  - 1b2d261d boot: zephyr: flash_map: Fix unused argument
  - 413eb384 boot: zephyr: flash_map: Fix missing include
  - 15b36f91 boot: zephyr: kconfig: enable dependencies of Mbed TLS
    Kconfig option
  - f6e8e88a boot: bootutil: Move erase function location
  - 5ef87c79 boot: zephyr: kconfig: Fix BOOT_SWAP_USING_MOVE
    description
  - bc18d7da boot: boot_serial: Fix issue with CBOR and setting
    image state

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>

Author: nordicjm

west.yml

@@ -308,7 +308,7 @@ manifest:
       groups:
         - crypto
     - name: mcuboot
-      revision: 81315483fcbdf1f1524c2b34a1fd4de6c77cd0f4
+      revision: 990b1fcb367e27056b282f183e819964fdbfe907
       path: bootloader/mcuboot
       groups:
         - bootloader