ARM: dts: msm: Update gfx clock corners for SDM450

New frequency table is required to be supported for GPU clients,
update the gfxfreq-corner table for the same.

Change-Id: Ia1daf6e06766f0e7299d1e32a907c5d12b713781
Signed-off-by: Shefali Jain <shefjain@codeaurora.org>