staging: rtl8188eu: remove unused array dB_Invert_Table

Array dB_Invert_Table is declared but not used, hence it is redundant
and can be removed.

Cleans up clang warning:
warning: ‘dB_Invert_Table’ defined but not used [-Wunused-const-variable=]

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