ide: convert ide-timing.h to ide-timings.c library (take 2)

* Don't include ide-timing.h in cs5535 and sis5513 host drivers
  (they don't need it currently).

* Convert ide-timing.h to ide-timings.c library and add CONFIG_IDE_TIMINGS
  config option to be selected by host drivers using the library.

While at it:

- fix ide_timing_find_mode() placement

v2:
* Add missing EXPORT_SYMBOLs. (Stephen Rothwell <sfr@canb.auug.org.au>)

There should be no functional changes caused by this patch.

Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/Makefile b/drivers/ide/Makefile
index a2b3f84..cb13506 100644
--- a/drivers/ide/Makefile
+++ b/drivers/ide/Makefile
@@ -14,6 +14,7 @@
 ide-core-y += ide.o ide-io.o ide-iops.o ide-lib.o ide-probe.o ide-taskfile.o
 
 # core IDE code
+ide-core-$(CONFIG_IDE_TIMINGS)		+= ide-timings.o
 ide-core-$(CONFIG_IDE_ATAPI)		+= ide-atapi.o
 ide-core-$(CONFIG_BLK_DEV_IDEPCI)	+= setup-pci.o
 ide-core-$(CONFIG_BLK_DEV_IDEDMA)	+= ide-dma.o