uboot-imx

moveconfig: Print a message for missing compiler

A common case for failed builds is a missing compiler. Print a message
for that case to tell the user concisely which compiler was expected
that was not found.

This patch also has the effect of not printing build errors any longer.
The next patch will add a switch to optionally bring that back.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>