Build: Fix typo "SIGNING"

Change-Id: Ie5c2d44698afb327d2c97dac94e997d986f43b28
Signed-off-by: Alamy Liu <alamy.liu@infineon.com>
diff --git a/cmake/install.cmake b/cmake/install.cmake
index 1e726ca..dd1ffc8 100644
--- a/cmake/install.cmake
+++ b/cmake/install.cmake
@@ -190,28 +190,28 @@
 
 ##################### Export image signing information #########################
 
-set(INSTALL_IMAGE_SIGINING_DIR ${TFM_INSTALL_PATH}/image_signing)
+set(INSTALL_IMAGE_SIGNING_DIR ${TFM_INSTALL_PATH}/image_signing)
 
 if(BL2)
     install(DIRECTORY bl2/ext/mcuboot/scripts
-            DESTINATION ${INSTALL_IMAGE_SIGINING_DIR})
+            DESTINATION ${INSTALL_IMAGE_SIGNING_DIR})
 
     if (MCUBOOT_ENC_IMAGES)
         install(FILES ${MCUBOOT_KEY_ENC}
-                DESTINATION ${INSTALL_IMAGE_SIGINING_DIR}/keys)
+                DESTINATION ${INSTALL_IMAGE_SIGNING_DIR}/keys)
     endif()
 
     install(FILES $<TARGET_OBJECTS:signing_layout_s>
-            DESTINATION ${INSTALL_IMAGE_SIGINING_DIR}/layout_files)
+            DESTINATION ${INSTALL_IMAGE_SIGNING_DIR}/layout_files)
 
     if(MCUBOOT_IMAGE_NUMBER GREATER 1)
         install(FILES $<TARGET_OBJECTS:signing_layout_ns>
-                DESTINATION ${INSTALL_IMAGE_SIGINING_DIR}/layout_files)
+                DESTINATION ${INSTALL_IMAGE_SIGNING_DIR}/layout_files)
 
         install(FILES ${MCUBOOT_KEY_NS}
-                DESTINATION ${INSTALL_IMAGE_SIGINING_DIR}/keys)
+                DESTINATION ${INSTALL_IMAGE_SIGNING_DIR}/keys)
     else()
         install(FILES ${MCUBOOT_KEY_S}
-                DESTINATION ${INSTALL_IMAGE_SIGINING_DIR}/keys)
+                DESTINATION ${INSTALL_IMAGE_SIGNING_DIR}/keys)
     endif()
 endif()