Revert "crypto: public_key: fix overflow during implicit conversion"

This reverts commit cfdd25cd which is
commit f985911b7bc75d5c98ed24d8aaa8b94c590f7c6a upstream and came in the
5.10.67 release.

It breaks the ABI for the public_key_verify_signature() function.  While
it does fix a useful thing, it shouldn't be an issue for any Android
devices so reverting should be safe.

Fixes: 5df14bba0056 ("crypto: public_key: fix overflow during implicit conversion")
Cc: Will Deacon <willdeacon@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I30ee9fec7d778b5d10483917975dd0ebe14aab88