Update mzero variant to 1.6.10 compliance

variants/arduino_mzero/linker_scripts/gcc/flash_with_bootloader.ld

@@ -47,6 +47,8 @@ SECTIONS
 {
 	.text :
 	{
+		__text_start__ = .;
+
 		KEEP(*(.isr_vector))
 		*(.text*)
 

variants/arduino_mzero/linker_scripts/gcc/flash_without_bootloader.ld

@@ -47,6 +47,8 @@ SECTIONS
 {
 	.text :
 	{
+		__text_start__ = .;
+
 		KEEP(*(.isr_vector))
 		*(.text*)
 

variants/arduino_mzero/variant.h

@@ -19,8 +19,8 @@
 #ifndef _VARIANT_ARDUINO_ZERO_
 #define _VARIANT_ARDUINO_ZERO_
 
-// The definitions here needs a SAMD core >=1.6.6
-#define ARDUINO_SAMD_VARIANT_COMPLIANCE 10606
+// The definitions here needs a SAMD core >=1.6.10
+#define ARDUINO_SAMD_VARIANT_COMPLIANCE 10610
 
 /*----------------------------------------------------------------------------
  *        Definitions