eMMC: add support for operations in RPMB partition

This patch adds functions for read, write and authentication
key programming for the Replay Protected Memory Block partition
in the eMMC.

Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>
Signed-off-by: Pierre Aubert <p.aubert@staubli.com>
diff --git a/lib/Makefile b/lib/Makefile
index 27e4f78..377ab13 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -35,6 +35,7 @@
 obj-$(CONFIG_PHYSMEM) += physmem.o
 obj-y += qsort.o
 obj-$(CONFIG_SHA1) += sha1.o
+obj-$(CONFIG_SUPPORT_EMMC_RPMB) += sha256.o
 obj-$(CONFIG_SHA256) += sha256.o
 obj-y	+= strmhz.o
 obj-$(CONFIG_TPM) += tpm.o