powerpc64le: Fix TFtype in sqrtf128 when using -mabi=ieeelongdouble

When building with -mlong-double-128 or -mabi=ibmlongdouble, TFtype
represents the IBM 128-bit extended floating point type, while KFtype
represents the IEEE 128-bit floating point type.
The soft float implementation of e_sqrtf128 had to redefine TFtype and
TF in order to workaround this issue.  However, this behavior changes
when -mabi=ieeelongdouble is used and the macros are not necessary.

	* sysdeps/powerpc/powerpc64/le/fpu/e_sqrtf128.c
	[__HAVE_FLOAT128_UNLIKE_LDBL] (TFtype, TF): Restrict TFtype
	and TF redirection to KFtype and KF only when the default
	long double type is not the IEEE 128-bit floating point type.

Signed-off-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>