staging:rtl8192u: remove typdef from enumeration HW90_BLOCK_E - Style

Checkpatch warns about the creation of new types in code. This patch simply
removes the typedef from the enumeration HW90_BLOCK_E to clear this
warning. There should be no impact on run time code execution.

Signed-off-by: John Whitmore <johnfwhitmore@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>