misc/test-errno-linux: Handle EINVAL from quotactl

In commit 3dd4d40b420846dd35869ccc8f8627feef2cff32 ("xfs: Sanity check
flags of Q_XQUOTARM call"), Linux 5.4 added checking for the flags
argument, causing the test to fail due to too restrictive test
expectations.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>