add support for future (Q4 2020) G4 devices

cmake/stm32/devices.cmake

@@ -612,6 +612,9 @@ set(STM32_ALL_DEVICES
     G473MB
     G473MC
     G473ME
+    G473PB
+    G473PC
+    G473PE
     G473QB
     G473QC
     G473QE
@@ -627,6 +630,9 @@ set(STM32_ALL_DEVICES
     G474MB
     G474MC
     G474ME
+    G474PB
+    G474PC
+    G474PE
     G474QB
     G474QC
     G474QE
@@ -638,11 +644,13 @@ set(STM32_ALL_DEVICES
     G474VE
     G483CE
     G483ME
+    G483PE
     G483QE
     G483RE
     G483VE
     G484CE
     G484ME
+    G484PE
     G484QE
     G484RE
     G484VE