Fix NMI interrupt handler alignment

as suggested at http://www.esp8266.com/viewtopic.php?f=6&t=4675&start=48#p46002

Author: igrr

tools/sdk/ld/eagle.app.v6.common.ld

@@ -78,6 +78,8 @@ SECTIONS
     *(.sdata2.*)
     *(.gnu.linkonce.s2.*)
     *(.jcr)
+    . = ALIGN(4);
+    _Pri_3_HandlerAddress = ABSOLUTE(.);
     _data_end = ABSOLUTE(.);
   } >dram0_0_seg :dram0_0_phdr