EISA: Move devlist.h out of obj to always

I put devlist.h into the wrong Makefile macro ("obj") to get it included
in "targets". Put it into "always" so nothing tries to link against it.
Solves CONFIG_EISA=y i386 build failure:

ld: vmlinux.a: member drivers/eisa/devlist.h in archive is not an object

Reported-by: Randy Dunlap <[e-mail]>
Closes: https://lore.kernel.org/all/[e-mail]
Fixes: dd09eb0e2cc4 ("EISA: Increase length of device names")
Signed-off-by: Kees Cook <[e-mail]>
Acked-by: Randy Dunlap <[e-mail]>
Tested-by: Randy Dunlap <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/eisa/Makefile

···
 # SPDX-License-Identifier: GPL-2.0
 # Makefile for the Linux device tree
 
-obj-$(CONFIG_EISA)	        += devlist.h eisa-bus.o
+always-$(CONFIG_EISA)		+= devlist.h
+obj-$(CONFIG_EISA)	        += eisa-bus.o
 obj-${CONFIG_EISA_PCI_EISA}     += pci_eisa.o
 
 # virtual_root.o should be the last EISA root device to initialize,