libc: minimal: rename private macro

As it turns out Xtensa SDK headers also define _Restrict, causing
havoc. As this was intended to be a private macro, rename it to something
less likely to cause a collision.

Change-Id: I0a7501a1af8cf87efb096872a91a7b44bd2bbdca
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
7 files changed