Expand OPENSSL_ia32cap_P to 64 bits. It might appear controversial, because

such operation can be considered as breaking binary compatibility. However!
OPNESSL_ia32cap_P is accessed by application through pointer returned by
OPENSSL_ia32cap_loc() and such change of *internal* OPENSSL_ia32cap_P
declaration is possible specifically on little-endian platforms, such as
x86[_64] ones in question. In addition, if 32-bit application calls
OPENSSL_ia32cap_loc(), it clears upper half of capability vector maintaining
the illusion that it's still 32 bits wide.