rustc_target: Use +spe for powerpcspe targets

Author: taiki-e

compiler/rustc_target/src/spec/targets/powerpc_unknown_linux_gnuspe.rs

@@ -25,7 +25,7 @@ pub(crate) fn target() -> Target {
         options: TargetOptions {
             cfg_abi: CfgAbi::Spe,
             endian: Endian::Big,
-            features: "+secure-plt,+msync".into(),
+            features: "+secure-plt,+msync,+spe".into(),
             mcount: "_mcount".into(),
             ..base
         },

compiler/rustc_target/src/spec/targets/powerpc_unknown_linux_muslspe.rs

@@ -25,7 +25,7 @@ pub(crate) fn target() -> Target {
         options: TargetOptions {
             cfg_abi: CfgAbi::Spe,
             endian: Endian::Big,
-            features: "+msync".into(),
+            features: "+msync,+spe".into(),
             mcount: "_mcount".into(),
             ..base
         },

compiler/rustc_target/src/spec/targets/powerpc_wrs_vxworks_spe.rs

@@ -26,7 +26,7 @@ pub(crate) fn target() -> Target {
             cfg_abi: CfgAbi::Spe,
             endian: Endian::Big,
             // feature msync would disable instruction 'fsync' which is not supported by fsl_p1p2
-            features: "+secure-plt,+msync".into(),
+            features: "+secure-plt,+msync,+spe".into(),
             ..base
         },
     }