sata_rcar: Remove ata_host_alloc() error printing

ata_host_alloc() can only fail due to memory allocation failures.
Hence there is no need to print a message, as the memory allocation core
code already takes care of that.

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jens Axboe <axboe@kernel.dk>