Compute kSortKeyViewNumBits automatically. (#2796)
Compute kSortKeyViewNumBits automatically. (#2796)

Compute kSortKeyViewNumBits automatically via log2(BGFX_CONFIG_MAX_VIEWS), so that we could change BGFX_CONFIG_MAX_VIEWS to be above 2^10 = 1024 without changing the `bgfx` source code.
One possible problem with this approach is running out of bits, so maybe we could assert for that, I am not sure where to do it and how many bits we can use though.
Using `bx::uint32_cntlz` because `bx::log2` is not constexpr.
Tested on linux opengl with BGFX_CONFIG_MAX_VIEWS=4096, seems to work.
LWJGL-CI/bgfx,bkaradzic/bgfx,LWJGL-CI/bgfx,bkaradzic/bgfx,LWJGL-CI/bgfx,LWJGL-CI/bgfx,bkaradzic/bgfx,bkaradzic/bgfx