Documenation/laptops: rename and update hpfall.c

Dell kernel driver dell-smo8800 provides same freefall interface as hp_accel so
program hpfall.c works also on Dell laptops. So rename it to freefall.c.

Dell driver does not provide hp::hddprotect led so make sure that freefall.c
works also if hp::hddprotect does not exist in sysfs.

Additionally write info to syslog.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Cc: Sonal Santan <sonal.santan@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/laptops/00-INDEX b/Documentation/laptops/00-INDEX
index d13b9a9..d399ae1 100644
--- a/Documentation/laptops/00-INDEX
+++ b/Documentation/laptops/00-INDEX
@@ -8,8 +8,8 @@
 	- information on hard disk shock protection.
 dslm.c
 	- Simple Disk Sleep Monitor program
-hpfall.c
-	- (HP) laptop accelerometer program for disk protection.
+freefall.c
+	- (HP/DELL) laptop accelerometer program for disk protection.
 laptop-mode.txt
 	- how to conserve battery power using laptop-mode.
 sony-laptop.txt