Fixed VFP detection through compiler defines.

Fixed VFP detection through compiler defines.

BUG=http://code.google.com/p/v8/issues/detail?id=1996
TEST=none

Review URL: https://chromiumcodereview.appspot.com/9669003
Patch from Rodolph Perfetta <rodolph.perfetta@gmail.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@10993 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Change-Id: I5534563915caa74ec458243415d5d56c2be074d2
Reviewed-by: Simon Hausmann <simon.hausmann@nokia.com>
Reviewed-by: Johannes Zellner <johannes.zellner@nokia.com>