arch/tile: add Tilera's <arch/sim.h> header as an open-source header

This change adds one of the Tilera standard <arch> headers to the set
of headers shipped with Linux.  The <arch/sim.h> header provides
methods for programmatically interacting with the Tilera simulator.

The current <arch/sim.h> provides inline assembly for the _sim_syscall
function, so the declaration and definition previously provided
manually in Linux are no longer needed.  We now use the standard
sim_validate_lines_evicted() method from <arch/sim.h> rather than
rolling our own direct call to sim_syscall().

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile/include/asm/system.h

@@ -217,13 +217,6 @@ int hardwall_deactivate(struct task_struct *task);
 } while (0)
 #endif
 
-/* Invoke the simulator "syscall" mechanism (see arch/tile/kernel/entry.S). */
-extern int _sim_syscall(int syscall_num, ...);
-#define sim_syscall(syscall_num, ...) \
-	_sim_syscall(SIM_CONTROL_SYSCALL + \
-		((syscall_num) << _SIM_CONTROL_OPERATOR_BITS), \
-		## __VA_ARGS__)
-
 /*
  * Kernel threads can check to see if they need to migrate their
  * stack whenever they return from a context switch; for user