arch: rename the SUPPORT_XXX options

First, 'SUPPORT' should be spelled 'SUPPORTS'.

Second, 'SUPPORT_XXX' really means 'supports --with-xxx', so rename the
affected options accordingly. Update the affected archs to match the new
namings.

Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 reporter_name="Yann E. MORIN"

 reporter_url="http://ymorin.is-a-geek.org/projects/crosstool"

 reporter_comment="EXPERIMENTAL MIPS-64 n32 toolchain."