Sanify Teensy linker script

There were a bunch of specially named sections that were either not used
or used for something different than their name, and they were all
unnecessary.

Change-Id: I378f6affdc0cd208c876aa00ca2f80d9b53abce1
diff --git a/motors/medium_salsa.cc b/motors/medium_salsa.cc
index 1a899b1..1fbe9a6 100644
--- a/motors/medium_salsa.cc
+++ b/motors/medium_salsa.cc
@@ -20,9 +20,9 @@
 void __stack_chk_fail(void);
 
 extern char *__brkval;
-extern unsigned long _ebss;
-extern unsigned long _sram;
-extern unsigned long _estack;
+extern uint32_t __bss_ram_start__[];
+extern uint32_t __heap_start__[];
+extern uint32_t __stack_end__[];
 
 }  // extern "C"
 
@@ -51,14 +51,14 @@
   // Give everything a chance to get going.
   delay(100);
 
-  printf("Ram start:   %p\n", &_sram);
-  printf("Heap start:  %p\n", &_ebss);
+  printf("Ram start:   %p\n", __bss_ram_start__);
+  printf("Heap start:  %p\n", __heap_start__);
   printf("Heap end:    %p\n", __brkval);
-  printf("Stack start: %p\n", &_estack);
+  printf("Stack start: %p\n", __stack_end__);
 
   GPIOC_PSOR = 1 << 5;
-
   while (true) {}
+
   return 0;
 }