Update kvmtool version

Update to the latest version (with attestation support)

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

package/kvmtool-cca/kvmtool.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-KVMTOOL_CCA_VERSION = cca/dtb
+KVMTOOL_CCA_VERSION = 2f8ad61e
 KVMTOOL_CCA_SITE = https://git.codelinaro.org/linaro/dcap/kvmtool.git
 KVMTOOL_CCA_SITE_METHOD = git
 KVMTOOL_CCA_DEPENDENCIES = \