The building of the 'software/' directory will fail if the project
doesn't know the path to 'vme-bridge', 'fpga-mgr-backpoirt', 'fmc',
'i2c', and 'spi' projects.
Thus, to make the error more clear, let the build system directly point
out that a project is missing, instead of complaining for missing
Signed-off-by: Vaibhav Gupta <firstname.lastname@example.org>