hwc: use proper scaler limits for OMAP3

The DSS scaler limits were apparently copied blindly from the OMAP4 HWC.
Use the OMAP3 limits (gleaned from drivers/video/omap2/dss/dispc.c in
the kernel source) instead:

* Decimation not supported (max decimation factor == 1)
* Maximum DSS FCLK 173 MHz

Change-Id: I1e266848c90876a595c62abc3082b0190282809e
hwc: don't vsync after swap in omap3_hwc_set()

SurfaceFlinger is responsible for waiting for vsync since 4.1, so we
should not do it here.

Change-Id: I0e66f2ccdc9bf0905d1ba839d9043a3d997eed7d