.travis.yml: explicitly request sudo

Without this, builds default to using new Travis CI infra-structure which
does no allow sudo. The builds need sudo in order to install the ELDK
compilers. Consequently, almost all builds fail without this.

I suspect that existing Travis CI users have not noticed this because
their accounts or builds have been grand-fathered into backwards-
compatible default settings, whereas I just set up a new build from
scratch and received new default settings.

Cc: Wolfgang Denk <[email protected]>
Cc: Heiko Schocher <[email protected]>
Cc: Tom Rini <[email protected]>
Cc: Daniel Schwierzeck <[email protected]>
Cc: Andreas Färber <[email protected]>
Signed-off-by: Stephen Warren <[email protected]>
Acked-by: Heiko Schocher <[email protected]>

.travis.yml

@@ -3,6 +3,8 @@
 
 # build U-Boot on Travis CI - https://travis-ci.org/
 
+sudo: true
+
 language: c
 
 addons: