r11951 changed the existing check for the __SOFTFP__ define in ARM platforms
to a check for __SOFTP. Most other programs look for __SOFTFP__ [1], so
look for both to increase the chances of not erroring out when using GCC 4.5.

[1] Based on http://codesearch.debian.net/search?q=__SOFTFP__ vs
    http://codesearch.debian.net/search?q=__SOFTFP[^_]

BUG=v8:2140
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/22210002

Patch from Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16070 ce2b1a6d-e550-0410-aec6-3dcde31c8c00