install: allow to use last block for embedding

Devices such as ODROIDs have binaries which use every single block for embedding. Do not raise an error when binaries are touching, but not overlapping, each other when embedding these binaries during installation.

Example:

• Binary size: 15360 bytes
• Block size: 512 bytes
• Start current binary block: 1
• Start next binary block: 31

==> 30 blocks x 512 bytes = 15360 bytes

I tested this change on ODROIDs and they just boot fine, moreover, the official ODROID flashing script also allow this.