Update targets.py

Make armcc the default compiler for atmel boards

Author: sg-

workspace_tools/targets.py

@@ -1601,7 +1601,7 @@ def __init__(self):
         self.extra_labels = ['Atmel', 'SAM_CortexM0+', 'SAMR21']
         self.macros = ['__SAMR21G18A__', 'I2C_MASTER_CALLBACK_MODE=true', 'EXTINT_CALLBACK_MODE=true', 'USART_CALLBACK_MODE=true', 'TC_ASYNC=true']
         self.supported_toolchains = ["GCC_ARM"]
-        self.default_toolchain = "GCC_ARM"
+        self.default_toolchain = "ARM"
 
 class SAMD21J18A(Target):
     def __init__(self):
@@ -1610,7 +1610,7 @@ def __init__(self):
         self.extra_labels = ['Atmel', 'SAM_CortexM0+', 'SAMD21']
         self.macros = ['__SAMD21J18A__', 'I2C_MASTER_CALLBACK_MODE=true', 'EXTINT_CALLBACK_MODE=true', 'USART_CALLBACK_MODE=true', 'TC_ASYNC=true']
         self.supported_toolchains = ["GCC_ARM"]
-        self.default_toolchain = "GCC_ARM"
+        self.default_toolchain = "ARM"
 
 class SAMD21G18A(Target):
     def __init__(self):
@@ -1619,7 +1619,7 @@ def __init__(self):
         self.extra_labels = ['Atmel', 'SAM_CortexM0+', 'SAMD21']
         self.macros = ['__SAMD21G18A__', 'I2C_MASTER_CALLBACK_MODE=true', 'EXTINT_CALLBACK_MODE=true', 'USART_CALLBACK_MODE=true', 'TC_ASYNC=true']
         self.supported_toolchains = ["GCC_ARM"]
-        self.default_toolchain = "GCC_ARM"
+        self.default_toolchain = "ARM"
 
 
 # Get a single instance for each target