syscall: Add sys_unlink

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

include/syscall-codes.h

@@ -20,6 +20,7 @@
 #define __NR_nanosleep		35
 #define __NR_getpid		39
 #define __NR_exit		60
+#define __NR_unlink		87
 
 #else /* CONFIG_X86_64 */
 # error x86-32 bit mode not yet implemented

include/syscall.h

@@ -166,6 +166,11 @@ static always_inline unsigned long sys_getpid(void)
 	return syscall0(__NR_getpid);
 }
 
+static always_inline long sys_unlink(char *pathname)
+{
+	return syscall1(__NR_unlink, (unsigned long)pathname);
+}
+
 /*
  * Note this call expects a signal frame on stack
  * (regs->sp) so be very carefull here!