ide-pci-generic: kill the unused ifdef/endif/MODULE code

with module_param macro, the __setup code can be killed now:
	const __setup("all-generic-ide", ide_generic_all_on);

and the module name "generic.ko" is not descriptive to its functionality,
can be changed in Makefile, the "ide-pci-generic.ko" is better.

the ide-pci-generic.all-generic-ide parameter also documented
in Documentation/kernel-parameters.txt

Signed-off-by: Denis Cheng <crquan@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>