Revert "[WATCHDOG] make watchdog/hpwdt.c:asminline_call() static"

The driver needs the asmlinkage tag and the CFLAGS line in the Makefile.
Without it the driver doesn't work.

Signed-off-by: Thomas Mingarelli <Thomas.Mingarelli@hp.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>