staging: r8188eu: remove duplicate psta check

We do not need the psta check in the while loop of rtw_xmitframe_coalesce.
psta is already checked near the start of the function and is not modified
afterwards.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/20221230180646.91008-9-martin@kaiser.cx


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>