Apply suggestions from code review

Co-authored-by: Sebastian Bøe <Sebastian.boe@nordicsemi.no>

Author: karstenkoenig

subsys/sdfw_services/services/psa_crypto/Kconfig

@@ -22,16 +22,17 @@ config SSF_PSA_CRYPTO_SERVICE_OUT_BOUNCE_BUFFERS
 		all PSA [inout] and [out] structures that are not aligned to the DCache DataUnit size.
 		When this option is disabled, the PSA Crypto service will never use bounce buffers,
 		and the application must ensure that the structures are cache-safe.
-		The structures are cache-safe if there is no writes locally to any of the DataUnits
+		The structures are cache-safe if there are no writes locally to any of the DataUnits
 		that contain the structure getting written from the remote.
 
 if SSF_PSA_CRYPTO_SERVICE_OUT_BOUNCE_BUFFERS
 
 config SSF_PSA_CRYPTO_SERVICE_OUT_HEAP_SIZE
-	int "Size of the heap buffer used for out buffer"
+	int "Size of the heap used to buffer output from PSA function calls"
 	default 4096
 	help
-	  Size of the heap buffer used for out buffer
+	  Size of the heap buffer used for out buffer.
+	  Reducing the size may trigger PSA_ERROR_INSUFFICIENT_MEMORY in PSA calls.
 
 endif # SSF_PSA_CRYPTO_SERVICE_OUT_BOUNCE_BUFFERS