dts: Rename DW APB timer compatible strings

"dw-apb-timer-osc" and "dw-apb-timer-sp" are the same implementation of the
DW APB timer, just fed by different clocks. Thus, deprecate both
"dw-apb-timer-osc" and "dw-apb-timer-sp" in lieu of "dw-apb-timer".

Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
Reviewed-by: Pavel Machek <pavel@denx.de>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
CC: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
CC: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
CC: Jamie Iles <jamie@jamieiles.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Pavel Machek <pavel@denx.de>
Cc: devicetree@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Olof Johansson <olof@lixom.net>

v3:
- Split out a separate that cleans up the timer entries and clock information.
- Clearly states which binding is deprecated in the bindings doc.

v2:
- Deprecate the "dw-apb-timer-osc" and "dw-apb-timer-sp" but maintain
  backwards compatibility in the driver.