iwlwifi: clarify NOCOPY/DUP documentation
iwlwifi: clarify NOCOPY/DUP documentation

Clarify the documentation to indicate that these
flags can only be used at the end, i.e. after them
a copy TFD (no flags set) is invalid.

Reported-by: Inbal Hacohen <9e09763dbc63ba5a6750892c389d8b102cd18c14@intel.com>
Reviewed-by: Emmanuel Grumbach <643a80aaf16a8332d6a70921c14d4bb265446494@intel.com>
Signed-off-by: Johannes Berg <bff32994ff0f8d048f262a8388145a71b6071bfe@intel.com>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas