kernel-build: Make all errors in the build script fatal

Make any error in the build script fatal, rather than checking for an
error in most places.

Change-Id: Ia043c492e367b500cff02cb7b347182534cc9385
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
1 file changed