Correctly handle missing cached_memory.

[maleadt]

Probably fixes https://discourse.julialang.org/t/flux-60-minute-blitz-weird-error-when-using-gpu/73537

[codecov]

Codecov Report

Merging #1295 (40be487) into master (35d8147) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1295   +/-   ##
=======================================
  Coverage   78.94%   78.94%           
=======================================
  Files         119      119           
  Lines        8650     8650           
=======================================
  Hits         6829     6829           
  Misses       1821     1821           

Impacted Files	Coverage Δ
lib/cudnn/convolution.jl	67.05% <100.00%> (ø)

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[ToucheSir]

Confirmed no errors raised running with this locally.

[DhairyaLGandhi]

Awesome! Per https://discourse.julialang.org/t/flux-60-minute-blitz-weird-error-when-using-gpu/73537/7?u=dhairyagandhi96 this should resolve the OP as well. Let's merge this once we get a reply on the thread about the version of the driver. Fwiw, it would work on new CUDA drivers so Flux's ci wouldn't catch it easily.