drivers/crypto/fsl: fix snooping for write transactions

HW coherency won't work properly for CAAM write transactions
if AWCACHE is left to default (POR) value - 4'b0001.
It has to be programmed to 4'b0010.

For platforms that have HW coherency support:
-PPC-based: the update has no effect; CAAM coherency already works
due to the IOMMU (PAMU) driver setting the correct memory coherency
attributes
-ARM-based: the update fixes cache coherency issues,
since IOMMU (SMMU) driver is not programmed to behave similar to PAMU

Fixes: b9eebfad ("fsl_sec: Add hardware accelerated SHA256 and SHA1")
Signed-off-by: Horia Geantă <horia.geanta@freescale.com>
Reviewed-by: Aneesh Bansal <aneesh.bansal@freescale.com>
Reviewed-by: Mingkai Hu <Mingkai.Hu@freescale.com>
Acked-by: Ruchika <Gupta&lt;ruchika.gupta@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>