staging: rtl8188eu: core: rtw_xmit: Remove extra braces

Remove the braces {} in the following cases:
- when there is a single branch with a single statement.
- when both branches have a single statement

The modifications improve the coding style.
Issues found by checkpatch.pl script.

Signed-off-by: Georgiana Rodica Chelu <georgiana.chelu93@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>