ARM: omap1: fix !ARCH_OMAP1_ANY link failures

While compile-testing randconfig builds for the upcoming boardfile
removal, I noticed that an earlier patch of mine was completely
broken, and the introduction of CONFIG_ARCH_OMAP1_ANY only replaced
one set of build failures with another one, now resulting in
link failures like

ld: drivers/video/fbdev/omap/omapfb_main.o: in function `omapfb_do_probe':
drivers/video/fbdev/omap/omapfb_main.c:1703: undefined reference to `omap_set_dma_priority'
ld: drivers/dma/ti/omap-dma.o: in function `omap_dma_free_chan_resources':
drivers/dma/ti/omap-dma.c:777: undefined reference to `omap_free_dma'
drivers/dma/ti/omap-dma.c:1685: undefined reference to `omap_get_plat_info'
ld: drivers/usb/gadget/udc/omap_udc.o: in function `next_in_dma':
drivers/usb/gadget/udc/omap_udc.c:820: undefined reference to `omap_get_dma_active_status'

I tried reworking it, but the resulting patch ended up much bigger than
simply avoiding the original problem of unused-function warnings like

arch/arm/mach-omap1/mcbsp.c:76:30: error: unused variable 'omap1_mcbsp_ops' [-Werror,-Wunused-variable]

As a result, revert the previous fix, and rearrange the code that
produces warnings to hide them. For mcbsp, the #ifdef check can
simply be removed as the cpu_is_omapxxx() checks already achieve
the same result, while in the io.c the easiest solution appears to
be to merge the common map bits into each soc specific portion.
This gets cleaned in a nicer way after omap7xx support gets dropped,
as the remaining SoCs all have the exact same I/O map.

Fixes: 615dce5b ("ARM: omap1: fix build with no SoC selected")
Cc: stable@vger.kernel.org
Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>