west.yml: MCUboot synchronization from upstream

Update Zephyr fork of MCUboot to revision:
  20f98e0a975c24864872e0df5701eb1082e9c957

  - 20f98e0a Updates for 2.2.0-rc1 release
  - 7a33bcaa boot: bootutil: loader: Add include for flash
    function
  - 8a9627d9 boot/zephyr/boards: nrf54h20dk 'iron' board
    configuration
  - de7a9dc5 zephyr: Disable SPI_NOR by default for
    nrf7002dk/nrf5340/cpuapp
  - 5aed4245 swap_move: correct appsize calcs and warning
  - 454c033f bootutil: swap-scratch: Fix conflicts after support
    of devices w/o erase
  - 572b8fb2 boot: zephyr: flash_map_extended: Add pointless
    workaround for clang
  - 091af82e boot/zephyr: nrf54h20dk adaptations
  - ed434f33 boot: bootutil: Fix clash of STRUCT_PACKED definition
  - 33ad4973 boot: zephyr: add support for mcx_n9xx_evk
  - 881608eb boot/zephyr: Use MCUBOOT_RAM_LOAD instead of
    CONFIG_BOOT_RAM_LOAD
  - 993c2ff8 boot/bootutil/ram_load: Add flash area pointer to
    bootloader state
  - 8b7c7cc9 zephyr: flash map: fix comparison signedness
  - b92d4dd7 boot: zephyr: Only supply MBEDTLS config file path
    if set
  - 9fa0c6b5 zephyr: Fix translation of PSA Kconfig to MCUboot
    config
  - 2d681da4 bootutil: Fix ed25519 pure signature verification

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