crypto: caam - make write transactions bufferable on PPC platforms

Previous change (see "Fixes" tag) to the MCFGR register
clears AWCACHE[0] ("bufferable" AXI3 attribute) (which is "1" at POR).

This makes all writes non-bufferable, causing a ~ 5% performance drop
for PPC-based platforms.

Rework previous change such that MCFGR[AWCACHE]=4'b0011
(bufferable + cacheable) for all platforms.
Note: For ARM-based platforms, AWCACHE[0] is ignored
by the interconnect IP.

Cc: <stable@vger.kernel.org> # 4.3+
Fixes: f1096749 ("crypto: caam - fix snooping for write transactions")
Signed-off-by: Horia Geant? <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/ctrl.c

@@ -534,8 +534,8 @@ static int caam_probe(struct platform_device *pdev)
 	 * long pointers in master configuration register
 	 */
 	clrsetbits_32(&ctrl->mcr, MCFGR_AWCACHE_MASK, MCFGR_AWCACHE_CACH |
-		      MCFGR_WDENABLE | (sizeof(dma_addr_t) == sizeof(u64) ?
-					MCFGR_LONG_PTR : 0));
+		      MCFGR_AWCACHE_BUFF | MCFGR_WDENABLE |
+		      (sizeof(dma_addr_t) == sizeof(u64) ? MCFGR_LONG_PTR : 0));
 
 	/*
 	 *  Read the Compile Time paramters and SCFGR to determine