meta: Rename SITEINFO_ENDIANESS to SITEINFO_ENDIANNESS

meta: Rename SITEINFO_ENDIANESS to SITEINFO_ENDIANNESS

There is this discrepency in spelling. Lets fix it in
core. There are lot of layers using SITEINFO_ENDIANNESS
This was shielded since meta-oe had its own copy of
siteinfo class. But that class has now been deleted in
favor of oe-core

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>