v3dv: ensure at least V3D_CL_MAX_INSTR_SIZE bytes in last CL instruction

v3dv: ensure at least V3D_CL_MAX_INSTR_SIZE bytes in last CL instruction

The CLE parser in the sim will read this many bytes for each instruction
in a CL, so we should ensure we have at least that many bytes available
in the BO when reading the last instruction, otherwise we can trigger
a GMP violation. It is not clear whether this behavior applies to real
hardware too.

cc: mesa-stable

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21162>
(cherry picked from commit c2601f06908434aaddd6b1db5e995bbda22d2a72)