irda: Removed all unused timeval variables

In the file au1k_ir.c & via-ircc.h, there were two unused definitions of the
timeval type members, this commit therefore removes this unneeded code.

In other three files, the same problem is the rx_time member is only ever
written, never read, so removed it entirely.

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>