Make ldbl-128 getpayload, setpayload functions use _Float128.
When I added the getpayload and setpayload functions I failed to make
the ldbl-128 functions use the _Float128 type name like most other
ldbl-128 functions do in preparation for being used to implement *f128
functions. This patch fixes them to use that name.
Tested for mips64.
* sysdeps/ieee754/ldbl-128/s_getpayloadl.c (getpayloadl): Use
_Float128 instead of long double.
* sysdeps/ieee754/ldbl-128/s_setpayloadl_main.c (FUNC): Likewise.