Fix tier level for 5 thumb bare-metal ARM targets

Author: cezarbbb

compiler/rustc_target/src/spec/targets/thumbv7a_none_eabi.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target: "thumbv7a-none-eabi".into(),
         metadata: TargetMetadata {
             description: Some("Thumb-mode Bare Armv7-A".into()),
-            tier: Some(2),
+            tier: Some(3),
             host_tools: Some(false),
             std: Some(false),
         },

compiler/rustc_target/src/spec/targets/thumbv7a_none_eabihf.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target: "thumbv7a-none-eabihf".into(),
         metadata: TargetMetadata {
             description: Some("Thumb-mode Bare Armv7-A, hardfloat".into()),
-            tier: Some(2),
+            tier: Some(3),
             host_tools: Some(false),
             std: Some(false),
         },

compiler/rustc_target/src/spec/targets/thumbv7r_none_eabi.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target: "thumbv7r-none-eabi".into(),
         metadata: TargetMetadata {
             description: Some("Thumb-mode Bare Armv7-R".into()),
-            tier: Some(2),
+            tier: Some(3),
             host_tools: Some(false),
             std: Some(false),
         },

compiler/rustc_target/src/spec/targets/thumbv7r_none_eabihf.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target: "thumbv7r-none-eabihf".into(),
         metadata: TargetMetadata {
             description: Some("Thumb-mode Bare Armv7-R, hardfloat".into()),
-            tier: Some(2),
+            tier: Some(3),
             host_tools: Some(false),
             std: Some(false),
         },

compiler/rustc_target/src/spec/targets/thumbv8r_none_eabihf.rs

@@ -7,7 +7,7 @@ pub(crate) fn target() -> Target {
         llvm_target: "thumbv8r-none-eabihf".into(),
         metadata: TargetMetadata {
             description: Some("Thumb-mode Bare Armv8-R, hardfloat".into()),
-            tier: Some(2),
+            tier: Some(3),
             host_tools: Some(false),
             std: Some(false),
         },