buildroot

Prefer 'printf' over 'echo -e' (for portability)

support/dependencies/dependencies.sh uses #!/bin/sh shebang. It is not
guaranteed that /bin/sh provides an 'echo' implementation that
understands the '-e' flag (interpret backslash escape chars). For
example, dash doesn't.

'printf' is more portable (it must interpret backslash escape chars,
according to POSIX), so use that.

NOTE: Before the previous commit, the dependencies.sh script used
/bin/echo instead of the shell built-in. That's probably why this hasn't
come up before.

Signed-off-by: Bjørn Forsman <bjorn.forsman@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>