[Blackfin] serial driver: fix bug - should not wait for the TFI bit, just clear it when tx stop.
[Blackfin] serial driver: fix bug - should not wait for the TFI bit, just clear it when tx stop.

Signed-off-by: Sonic Zhang <c93d368f28096020dd845c4879a931e9d13ab23f@analog.com>
Signed-off-by: Bryan Wu <465f0e91e61585f5bc1128e7fe63296c33a56926@analog.com>


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