lima: fix vertex shader uniform buffer size

lima: fix vertex shader uniform buffer size

In some cases when switching shader programs, mesa does not switch the
currently set pipe_constant_buffer, which keeps pointing to the one
previously set.
If the two shader programs have a different number of uniforms, the size
of the constant buffer may be different and this needs to be considered
while generating the next draw command.
This patch fixes the uniform buffer creation in the lima vertex shader
command to avoid an out of bounds memcpy due to a previously set
pipe_constant_buffer.

Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Reviewed-by: Vasily Khoruzhick <anarsoul@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6701>