openlane(gf180): update PLACE_SITE

gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl

diff --git a/gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl b/gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl
index 386c72f..3589369 100644
--- a/gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl
+++ b/gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl
@@ -2,7 +2,7 @@
 
 # Placement site for core cells
 # This can be found in the technology lef
-set ::env(PLACE_SITE) "$::env(STD_CELL_LIBRARY)"
+set ::env(PLACE_SITE) "GF018hv5v_mcu_sc7"
 set ::env(PLACE_SITE_WIDTH) 0.56
 set ::env(PLACE_SITE_HEIGHT) 3.92