Move ast2600 to use hard float call convention

Before this change, the ast2600 binaries were built with the soft float
call convention, which allows them to run on systems that don't have
hard float FPUs.

Internally, this changes yocto to build like this:
CXX="arm-openbmc-linux-gnueabi-g++ \
         -march=armv7-a -mfpu=vfpv4-d16 -mfloat-abi=hard ...
CPP="arm-openbmc-linux-gnueabi-gcc \
         -march=armv7-a -mfpu=vfpv4-d16 -mfloat-abi=hard ...

Tested: Builds and boots on ast2600-EVB

Change-Id: I89a2579abfac9bcefd82010a69793bee3a8116e2
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
diff --git a/conf/machine/include/aspeed.inc b/conf/machine/include/aspeed.inc
index 05e4658..a2316cf 100644
--- a/conf/machine/include/aspeed.inc
+++ b/conf/machine/include/aspeed.inc
@@ -20,7 +20,7 @@
 SERIAL_CONSOLES ?= "115200;ttyS4"
 
 DEFAULTTUNE_aspeed-g5 ?= "arm1176jzs"
-DEFAULTTUNE_aspeed-g6 ?= "armv7a-vfpv4d16"
+DEFAULTTUNE_aspeed-g6 ?= "armv7ahf-vfpv4d16"
 
 UBOOT_ENTRYPOINT_aspeed-g4 ?= "0x40001000"
 UBOOT_ENTRYPOINT_aspeed-g5 ?= "0x80001000"