Tweak kernel.ld linker script so edata and end are set correctly

This change should hopefully resolve issues when compiling with newer versions
of GCC.

Author: fintelia

kern/kernel.ld

@@ -47,13 +47,13 @@ SECTIONS
 		*(.data)
 	}
 
-	PROVIDE(edata = .);
-
 	.bss : {
+		PROVIDE(edata = .);
 		*(.bss)
+		PROVIDE(end = .);
+		BYTE(0)
 	}
 
-	PROVIDE(end = .);
 
 	/DISCARD/ : {
 		*(.eh_frame .note.GNU-stack)