Replace "echo -e" with "printf" to have the same behavior in dash or bash

Replace "echo -e" with "printf" to have the same behavior in dash or bash

oe-core removed the prerequisite to have sh as bash. POSIX doesn't define
any options and furthermore allows 'echo -e' to be the default behavior.
This means that in dash 'echo -e' will actually print '-e' and interpret
backslashes by default. We use instead 'printf' builtin command with or
without '\n' to simulate 'echo -e' or 'echo -n'.
'printf' needs format while 'echo' can be used without any arguments. So
'echo >' was replaced by 'printf "" >'.
'echo' without '-n' flag adds a new line by default so to keep the same
behavior of two new lines while using 'echo "\n"', 'printf "\n\n"' is
used.

[YOCTO #3138]

(From OE-Core rev: a19880ad10ccb5d7d909dcf9de5c3dc58a0ebcd3)

Signed-off-by: Andrei Gherzan <andrei@gherzan.ro>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>