meta-ast2500: Tune for ARM1176JZ-S

Include tune-arm1176jz-s.inc in the ast2500 SoC include file and set its
default tune to the core-specific variable. This enables Thumb package
builds and adds a compiler tune for the ARM1176 core.

AST2500 BMC developers won't likely observed any differences other than
seeing in the build log:
TUNE_FEATURES     = "arm armv6  thumb arm1176jzs"

Tested: Inspected some packages with the bb utility that
TUNE_PKGARCH="armv6" and verified booting Zaius BMC.
Signed-off-by: Xo Wang <xow@google.com>
Change-Id: I70beab3d4e930b22dd4dd7b42e56971448396a7b
1 file changed