mwifiex: remove duplicate structure host_cmd_tlv

We already have 'struct mwifiex_ie_types_header' with same
definition. Hence host_cmd_tlv is removed in this patch.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>