[flang][openacc][openmp] Use #0 from hlfir.declare value when generating bound ops (#80317)

`getDataOperandBaseAddr` retrieve the address of a value when we need to
generate bound operations. When switching to HLFIR, we did not really
handle the fact that this value was then pointing to the result of a
hlfir.declare. Because of that the `#1` value was being used. `#0` value
is carrying the correct information about lowerbounds and should be
used. This patch updates the `getDataOperandBaseAddr` function to use
the correct result value from hlfir.declare.