staging: rtlwifi: remove redundant assignments to ul_enc_algo

Variable ul_enc_algo is being initialized with a value that is never
read, it is being set again in the following switch statements in
all of the case and default paths. Hence the unitialization is
redundant and can be removed.  Cleans up two clang warnings:

Value stored to 'ul_enc_algo' during its initialization is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>