updated arm links which had gone stale

app/views/pages/arm/overview.html.haml

@@ -19,6 +19,12 @@
   = ext_link "Dave’s", "http://www.davespace.co.uk/arm/introduction-to-arm/why-learn.html"
   site explains just about
   everything about the arm in nice and easy to understand terms.
+%p
+  Also a nice
+  = ext_link "assembler hack overview" , "https://github.com/cirosantilli/arm-assembly-cheat"
+  by Ciro Santilli, which has a section on system calls and links to
+  =ext_link "the SOURCE" , "https://github.com/torvalds/linux/blob/v4.17/arch/arm/tools/syscall.tbl"
+
 %p
   A nice series on thinkgeek, here is the integer
   =ext_link "division section" ,  "http://thinkingeek.com/2013/08/11/arm-assembler-raspberry-pi-chapter-15/"
@@ -33,9 +39,6 @@
   = ext_link "ARM1176JZF-S pdf is here" , "/arm/big_spec.pdf"
   or
   =ext_link "online" , "http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0553a/BABFADHJ.html"
-%p
-  A nice list of
-  =ext_link "Kernel calls" , "http://docs.cs.up.ac.za/programming/asm/derick_tut/syscalls.html"
 
 %h2 Virtual pi
 %p