In the traditional MIPS naming scheme, "mips" is used for
big-endian mips and "mipsel" is used for little-endian mips.
In V8 the "mips" build is little-endian, so the "mips" target is
renamed to "mipsel" to be compliant with the traditional MIPS
naming scheme.

This change is also required for supporting the Chromium project on MIPS.

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/10695114

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12047 ce2b1a6d-e550-0410-aec6-3dcde31c8c00