testsuite: Adjust two bfp test cases with has_arch_ppc64 [PR108729]

Two test cases scalar-test-data-class-12.c and vec-test-data-class-9.c
fail on Power9 BE testing at -m32, they adopts a built-in function
scalar_insert_exp which requires powerpc64 support.  This patch
is to make them to check has_arch_ppc64 effective target requirement.

	PR testsuite/108729

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/bfp/scalar-test-data-class-12.c: Adjust with
	has_arch_ppc64 effective target.
	* gcc.target/powerpc/bfp/vec-test-data-class-9.c: Likewise.

gcc/testsuite/gcc.target/powerpc/bfp/scalar-test-data-class-12.c

 /* { dg-do run { target { powerpc*-*-* } } } */
+/* { dg-require-effective-target has_arch_ppc64 } */
 /* { dg-require-effective-target p9vector_hw } */
 /* { dg-options "-mdejagnu-cpu=power9" } */
 

gcc/testsuite/gcc.target/powerpc/bfp/vec-test-data-class-9.c

 /* { dg-do run { target { powerpc*-*-* } } } */
+/* { dg-require-effective-target has_arch_ppc64 } */
 /* { dg-require-effective-target p9vector_hw } */
 /* { dg-options "-mdejagnu-cpu=power9" } */