Fixed the default size of the workspace array for MAGMA's SVD (#54875)
Summary:
The problem was that MAGMA might not set the value for the optimal size of the workspace array leaving it uninitialized. This is fixed by setting the default value for `wkopt` variable.
Fixes https://github.com/pytorch/pytorch/issues/54381 and https://github.com/pytorch/pytorch/issues/53976.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54875
Reviewed By: H-Huang
Differential Revision: D27437702
Pulled By: mruberry
fbshipit-source-id: bf61555abc4c50e8ef2dae933df24ce4d4fe4527
