freedreno/ir3: Fix sizing of the inputs/outputs array.

freedreno/ir3: Fix sizing of the inputs/outputs array.

If you have a struct, the var's base driver location is not the last
driver location that will be accessed in that var.  We have a shader
struct member with this number for us, already.  Fixes overflows in:

dEQP-GLES31.functional.program_interface_query.program_output.type.interface_blocks.out.named_block_explicit_location.struct.mat3x2

Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Jose Maria Casanova Crespo <jmcasanova@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4670>