esp_common: Fix issue with SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY not visible on c3

Create a common symbol name to use from linker.lf fragments

components/bt/linker.lf

@@ -1,5 +1,5 @@
 [mapping:bt]
 archive: libbt.a
 entries:
-    if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+    if ESP_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
         * (extram_bss)

components/esp32/ld/esp32_fragments.lf

@@ -107,7 +107,7 @@ entries:
     data -> dram0_data
     bss -> dram0_bss
     common -> dram0_bss
-    if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+    if ESP_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
         extram_bss -> extern_ram
     else:
         extram_bss -> dram0_bss

components/esp_common/Kconfig

@@ -304,4 +304,9 @@ menu "Common ESP-related"
     config ESP_MAC_ADDR_UNIVERSE_ETH
         bool
 
+    config ESP_ALLOW_BSS_SEG_EXTERNAL_MEMORY
+        # Invisible option that is set by SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY, but
+        # exists even if SPIRAM is not supported
+        bool
+
 endmenu # Common ESP-related

components/esp_common/Kconfig.spiram.common

@@ -93,6 +93,7 @@ config SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY
     bool "Allow .bss segment placed in external memory"
     default n
     depends on SPIRAM
+    select ESP_ALLOW_BSS_SEG_EXTERNAL_MEMORY
     help
         If enabled, variables with EXT_RAM_ATTR attribute will be placed in SPIRAM instead of internal DRAM.
         BSS section of `lwip`, `net80211`, `pp`, `bt` libraries will be automatically placed

components/esp_wifi/linker.lf

@@ -17,7 +17,7 @@ entries:
     if ESP32_WIFI_RX_IRAM_OPT = y:
         * (wifi_rx_iram)
 
-    if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+    if ESP_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
         * (extram_bss)
 
 [mapping:net80211]
@@ -29,5 +29,5 @@ entries:
     if ESP32_WIFI_RX_IRAM_OPT = y:
         * (wifi_rx_iram)
 
-    if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+    if ESP_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
         * (extram_bss)

components/lwip/linker.lf

@@ -86,5 +86,5 @@ entries:
 
     * (default)
 
-  if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+  if ESP_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
     * (extram_bss)