x86/Voyager: remove ISA quirk

Voyager has this ISA quirk (because Voyager has no ISA support):

 config ISA
 	bool "ISA support"
	depends on !X86_VOYAGER

There's a ton of x86 hardware that does not support ISA, and because
most ISA drivers cannot auto-detect in a safe way, the convention in
the kernel has always been to not enable ISA drivers if they are not
needed.

Voyager users can do likewise - no need for a Kconfig quirk.

Signed-off-by: Ingo Molnar <mingo@elte.hu>