west.yaml: MCUboot synchronization from upstream

Update Zephyr fork of MCUboot to revision:
  1558e7ab0aadb4eac11f03befb5ccd3fa3f0aafe

Brings following Zephyr relevant fixes:
 - 1558e7ab boot: zephyr: remove stm32 watchdog defines
 - 4420bb66 boot: zephyr: setup watchdog
 - 393af79e boot_serial: Update zcbor files from zcbor 0.7.0
 - a95a41b3 boot: bootutil: loader: Let image version comparison use
           build number
 - f7d8660e boot_serial: Fix include paths for zephyr builds
 - c7835371 bootutil: Add FIH for ED25519 sig verification
 - 186ac885 bootutil: Fix FIH return type for EC256
 - 5397c13d zephyr: serial_recovery: Fix broken CDC device selection
 - 918da26a bootutil: Provide boot_set_next function

Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>