ghs: replace the "-Wall" build option with the "-ghstd=last"

According to the Greenhills documentation, the "-Wall" option is
deprecated for use. Instead, the "-ghstd=last" option is recommended.
Compared with "-Wall", the "-ghstd=last" option can capture more
warnings and has stricter rules.

Signed-off-by: guoshichao <guoshichao@xiaomi.com>

arch/arm/src/cmake/ghs.cmake

@@ -60,7 +60,7 @@ endif()
 # Architecture flags
 
 add_link_options(-entry=__start)
-add_compile_options(--no_commons -Wall -Wshadow -Wundef -nostdlib)
+add_compile_options(--no_commons --ghstd=last -Wshadow -Wundef -nostdlib)
 add_compile_options(--option=305)
 
 if(CONFIG_DEBUG_CUSTOMOPT)

arch/arm/src/common/Toolchain.defs

@@ -410,7 +410,14 @@ ARCHOPTIMIZATION += --no_commons
 else
 ARCHOPTIMIZATION += -fno-common
 endif
-ARCHOPTIMIZATION += -Wall -Wshadow -Wundef
+
+ifeq ($(CONFIG_ARM_TOOLCHAIN_GHS),y)
+  ARCHOPTIMIZATION += --ghstd=last
+else
+  ARCHOPTIMIZATION += -Wall
+endif
+
+ARCHOPTIMIZATION += -Wshadow -Wundef
 
 ifeq ($(CONFIG_ARM_TOOLCHAIN_ARMCLANG),y)
   ARCHOPTIMIZATION += -nostdlib