atsam: Update code to use armcm_boot mechanism

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/atsam/Kconfig

@@ -55,6 +55,28 @@ config CLOCK_FREQ
     default 84000000 if MACH_SAM3X
     default 120000000 if MACH_SAM4
 
+config FLASH_START
+    hex
+    default 0x400000 if MACH_SAM4
+    default 0x80000
+
+config FLASH_SIZE
+    hex
+    default 0x80000
+
+config RAM_START
+    hex
+    default 0x20000000
+
+config RAM_SIZE
+    hex
+    default 0x18000 if MACH_SAM3X
+    default 0x20000 if MACH_SAM4
+
+config STACK_SIZE
+    int
+    default 512
+
 config USBSERIAL
     bool "Use USB for communication (instead of serial)"
     default y