[U-Boot] [ARM] one warning left for all ARM boards

[Albert ARIBAUD]

Hi all,

With the latest commits on u-boot/master, two obnoxious "attention"
messages were removed from ARM builds, but one still remains:

attention : -fstack-usage not supported for this target [enabled by
default]

This is with gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5).

doc/SPL/README.omap3 does indeed say that not all GCC releases have
-fstack-usage, and commit 4a30f1e8 from Tom Rini (Cc:) says it tests
for the option, but apparently testing for the option is not the same as
testing for the option on a given target...

How do we get rid of those warnings? Right now they appear for every
single ARM board built.

Amicalement,
-- 
Albert.