Fix detection of IBM Power8 machines (ISA 2.07)

An IBM POWER7 system with Power ISA 2.06 tried to execute
zfs_sha256_power8() - which should only be run on ISA 2.07
machines.

The detection is implemented via the zfs_isa207_available() call,
but this check was not used.

This pull request will fix this.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Signed-off-by: Low-power <msl0000023508@gmail.com>
Closes #14576

module/icp/algs/sha2/sha256_impl.c

@@ -151,9 +151,9 @@ const sha256_ops_t sha256_armv8_impl = {
 };
 
 #elif defined(__PPC64__)
-static boolean_t sha256_have_vsx(void)
+static boolean_t sha256_have_isa207(void)
 {
-	return (kfpu_allowed() && zfs_vsx_available());
+	return (kfpu_allowed() && zfs_isa207_available());
 }
 
 TF(zfs_sha256_ppc, tf_sha256_ppc);
@@ -165,7 +165,7 @@ const sha256_ops_t sha256_ppc_impl = {
 
 TF(zfs_sha256_power8, tf_sha256_power8);
 const sha256_ops_t sha256_power8_impl = {
-	.is_supported = sha256_have_vsx,
+	.is_supported = sha256_have_isa207,
 	.transform = tf_sha256_power8,
 	.name = "power8"
 };

module/icp/algs/sha2/sha512_impl.c

@@ -136,14 +136,14 @@ const sha512_ops_t sha512_ppc_impl = {
 	.name = "ppc"
 };
 
-static boolean_t sha512_have_vsx(void)
+static boolean_t sha512_have_isa207(void)
 {
-	return (kfpu_allowed() && zfs_vsx_available());
+	return (kfpu_allowed() && zfs_isa207_available());
 }
 
 TF(zfs_sha512_power8, tf_sha512_power8);
 const sha512_ops_t sha512_power8_impl = {
-	.is_supported = sha512_have_vsx,
+	.is_supported = sha512_have_isa207,
 	.transform = tf_sha512_power8,
 	.name = "power8"
 };