staging: wilc1000: Rename struct tstrRSSI to rssi_history_buffer

Rename struct tstrRSSI to rssi_history_buffer for clarity
and to remove camel casing.

Signed-off-by: Tahia Khan <tahia.khan@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>