Revert "Include modem.bin.md5sum in boot image."

This reverts commit d9e736f03cb46f407f3c8b68f5af328c35d12030.
Revert "Compute md5 for modem.bin to update modem.bin."

This reverts commit 86e9ea9e4bb9ae0ea8d18bb83e66a7a3f4190d5a.