Update revision for release tag 3.16.0-rc1

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/mk/config.mk b/mk/config.mk
index 7d7d9c6..1b13983 100644
--- a/mk/config.mk
+++ b/mk/config.mk
@@ -127,7 +127,7 @@
 # with limited depth not including any tag, so there is really no guarantee
 # that TEE_IMPL_VERSION contains the major and minor revision numbers.
 CFG_OPTEE_REVISION_MAJOR ?= 3
-CFG_OPTEE_REVISION_MINOR ?= 15
+CFG_OPTEE_REVISION_MINOR ?= 16
 
 # Trusted OS implementation version
 TEE_IMPL_VERSION ?= $(shell git describe --always --dirty=-dev 2>/dev/null || \