crypto: sa2ul - Fix leaks on failure paths with sa_dma_init()

The sa_dma_init() function doesn't release the requested dma channels
on all failure paths. Any failure in this function also ends up
leaking the dma pool created in sa_init_mem() in the sa_ul_probe()
function. Fix all of these issues.

Fixes: 7694b6ca ("crypto: sa2ul - Add crypto driver")
Signed-off-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Tero Kristo <kristo@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>