irda: sh_irda: remove driver

Remove the sh-irda driver as it appears to be unused since
c0bb9b30

 ("ARCH: ARM: shmobile: Remove ag5evm board support").

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>