msm: clock-8960: Add more gfx3d and vcodec frequencies for 8930ab

On 8930ab, gfx3d and vcodec maximum frequencies have been bumped
to 500MHz and 266MHz respectively. Therefore, update PLL15 frequency
to 1000MHz to support gfx3d clock at 500MHz and also update Fmax
values for both gfx3d and vcodec clocks.

Change-Id: Iff9bf097e501b978890da28100fe66b5d2a1830a
Signed-off-by: Seemanta Dutta <seemanta@codeaurora.org>