aco/ra: Fix counting of subdword variables in get_reg_create_vector

The loop variable "k" shadowed another variable in the outer scope, so
this loop had no actual effect.

Fixes: 52cc1f8237d ("aco: improve p_create_vector RA for sub-dword operands")
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7427>
1 file changed