armebv7r-none-eabihf: default to ARM mode

- remove +thumb2 that has not effect
- remove -mthumb

Tested on TMS570LS3137

src/ci/docker/disabled/dist-armebv7r-none-eabihf/Dockerfile

@@ -29,7 +29,7 @@ ENV PATH=$PATH:/$GCC_LINARO/bin
 ENV TARGET=armebv7r-none-eabihf
 
 ENV CC_armebv7r_none_eabihf=armeb-eabi-gcc \
-    CFLAGS_armebv7r_none_eabihf="-mthumb -march=armv7-r"
+    CFLAGS_armebv7r_none_eabihf="-march=armv7-r"
 
 ENV RUST_CONFIGURE_ARGS --disable-docs
 

src/librustc_target/spec/armebv7r_none_eabihf.rs

@@ -30,7 +30,7 @@ pub fn target() -> TargetResult {
             executables: true,
             relocation_model: "static".to_string(),
             panic_strategy: PanicStrategy::Abort,
-            features: "+v7,+thumb2,+vfp3,+d16,+fp-only-sp".to_string(),
+            features: "+v7,+vfp3,+d16,+fp-only-sp".to_string(),
             max_atomic_width: Some(32),
             abi_blacklist: super::arm_base::abi_blacklist(),
             emit_debug_gdb_scripts: false,