[llvm] [Xtensa] Fix XtensaELFObjectWriter. (PR #146731)

[Andrei Safronov via llvm-commits]

andreisfr wrote:

> Apologies that I did not inform you that XtensaMCExpr.h has been removed. In general when landing a patch out for a few days, it's best to test buildability..... llvm gets 100 commits a day and things change quickly...

Thank you for advice!

https://github.com/llvm/llvm-project/pull/146731