Replace TFM_CONFIG_USE_TRUSTZONE with CONFIG_TFM_USE_TRUSTZONE

For consistency with others with both prefixes

Signed-off-by: Chris Brand <chris.brand@cypress.com>
Change-Id: I0c9f17362dc5f19c534900d60c0b8d61ff012768
diff --git a/cmake/install.cmake b/cmake/install.cmake
index 6bbf6ac..6f45df6 100644
--- a/cmake/install.cmake
+++ b/cmake/install.cmake
@@ -19,7 +19,7 @@
 set(INSTALL_INTERFACE_LIB_DIR    ${TFM_INSTALL_PATH}/interface/lib)
 
 # export veneer lib
-if (TFM_CONFIG_USE_TRUSTZONE)
+if (CONFIG_TFM_USE_TRUSTZONE)
     install(FILES       ${CMAKE_BINARY_DIR}/secure_fw/s_veneers.o
             DESTINATION ${INSTALL_INTERFACE_LIB_DIR})
 endif()