manifest: Update sdk-mcuboot revision

Update sdk-mcuboot to include SPIM cleanup for nRF91 from PR:
nrfconnect/sdk-mcuboot#606

Signed-off-by: Diego Solano <diegosolano@gmail.com>

Author: diegosolano

west.yml

@@ -128,7 +128,7 @@ manifest:
           compare-by-default: true
     - name: mcuboot
       repo-path: sdk-mcuboot
-      revision: 8230615892bd06e59d3e6af7e423c6f74a4645ef
+      revision: 488e045e8427110d811b89e118910a9c03c61f4c
       path: bootloader/mcuboot
     - name: qcbor
       url: https://github.com/laurencelundblade/QCBOR