powerpc: Move around math-related Implies

Currently, powerpc, powerpc64, and powerpc64le imply the same set of
subdirectories from sysdeps/ieee754: flt-32, dbl-64, ldbl-128ibm, and
ldbl-opt.  In preparation for the transition of the long double format -
from IBM Extended Precision to IEEE 754 128-bits floating-point - on
powerpc64le, this patch splits the shared Implies file into three
separate files (one for each of the powerpc architectures), without
changing their contents.  Future patches will modify powerpc64le.

	* sysdeps/powerpc/Implies: Removed.  Previous contents copied to...
	* sysdeps/powerpc/powerpc32/Implies-after: ... here.
	* sysdeps/powerpc/powerpc64/be/Implies-after: ... here.
	* sysdeps/powerpc/powerpc64/le/Implies-before: ... and here.

ChangeLog

@@ -1,3 +1,11 @@
+2018-05-24  Tulio Magno Quites Machado Filho  <tuliom@linux.ibm.com>
+	    Gabriel F. T. Gomes  <gabriel@inconstante.eti.br>
+
+	* sysdeps/powerpc/Implies: Removed.  Previous contents copied to...
+	* sysdeps/powerpc/powerpc32/Implies-after: ... here.
+	* sysdeps/powerpc/powerpc64/be/Implies-after: ... here.
+	* sysdeps/powerpc/powerpc64/le/Implies-before: ... and here.
+
 2018-05-24  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/Implies: Remove

sysdeps/powerpc/powerpc64/be/Implies-after

@@ -0,0 +1,5 @@
+# On PowerPC we use the IBM extended long double format.
+ieee754/ldbl-128ibm
+ieee754/ldbl-opt
+ieee754/dbl-64
+ieee754/flt-32

sysdeps/powerpc/powerpc64/le/Implies-before

@@ -1 +1,6 @@
+# On PowerPC we use the IBM extended long double format.
+ieee754/ldbl-128ibm
+ieee754/ldbl-opt
+ieee754/dbl-64
+ieee754/flt-32
 ieee754/float128