Input: twl4030-pwrbutton - fix kernel-doc warning

Do not use kernel-doc style for comment describing contents of the
source file, as it trips the script:

scripts/kernel-doc -none drivers/input/misc/twl4030-pwrbutton.c
drivers/input/misc/twl4030-pwrbutton.c:2: info: Scanning doc for function twl4030
drivers/input/misc/twl4030-pwrbutton.c:33: warning: expecting prototype for twl4030(). Prototype was for PWR_PWRON_IRQ() instead
1 warnings

Also remove file name from the same comment - it it not the best idea
to have it as they tend to get stale when sources get moved or renamed.

Reported-by: Mirsad Todorovac <[e-mail]>
Tested-by: Mirsad Todorovac <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/misc/twl4030-pwrbutton.c

···
-/**
- * twl4030-pwrbutton.c - TWL4030 Power Button Input Driver
+/*
+ * TWL4030 Power Button Input Driver
  *
  * Copyright (C) 2008-2009 Nokia Corporation
  *