Staging: rtl8192e: Refactored rtllib_modes

Staging: rtl8192e: Refactored rtllib_modes

The initial reason for looking at this code was an
issue raised by checkpatch.pl:

     $ ./scripts/checkpatch.pl --terse -f drivers/staging/rtl8192e/rtllib_wx.c
     CHECK: Please use a blank line after function/struct/union/enum
     declarations

The additional blank line above the struct/before the headers is
just cleaner.

However, as it turns out since there is no str formatting required
One can replace the error prone str + size struct with a char array.
The rest of this patch fixes the usecases.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Signed-off-by: Felix Schlepper <f3sch.git@outlook.com>
Link: https://lore.kernel.org/r/4dbc4939e88a2c94f1819b4b0cc2c81dc332710b.1656667089.git.f3sch.git@outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>