Adding submodules for the GF180MCU PDK SRAM macros.

Fixes https://github.com/google/gf180mcu-pdk/issues/2.

Signed-off-by: Tim 'mithro' Ansell <tansell@google.com>
diff --git a/.gitmodules b/.gitmodules
index d9f68d1..f92d502 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -26,9 +26,9 @@
 	branch = main
 	shallow = true
 
-# gf180mcu_fd_bd_sram
-[submodule "libraries/gf180mcu_fd_bd_sram/latest"]
-	path = libraries/gf180mcu_fd_bd_sram/latest
-	url = https://github.com/google/globalfoundries-pdk-libs-gf180mcu_fd_bd_sram.git
+# gf180mcu_fd_ip_sram
+[submodule "macros/gf180mcu_fd_ip_sram/latest"]
+	path = macros/gf180mcu_fd_ip_sram/latest
+	url = https://github.com/google/globalfoundries-pdk-ip-gf180mcu_fd_ip_sram.git
 	branch = main
 	shallow = true
diff --git a/macros/gf180mcu_fd_ip_sram/latest b/macros/gf180mcu_fd_ip_sram/latest
new file mode 160000
index 0000000..343ab45
--- /dev/null
+++ b/macros/gf180mcu_fd_ip_sram/latest
@@ -0,0 +1 @@
+Subproject commit 343ab45497682f3f3f808ee4c79a8f92c5010636