bootloader: keep bootloader_common code to retention region

It is possible to utilize some of the routines related to otadata
partition validation, after firmware image is downloaded to RAM. Hence
these routines should be part of app cpu cache, so that they do not
get overwritten by firmware.

Signed-off-by: Mahavir Jain <mahavir@espressif.com>

components/bootloader/subproject/main/esp32.bootloader.ld

@@ -36,11 +36,12 @@ SECTIONS
   {
     . = ALIGN (16);
     _stext = .;
-    _text_start = ABSOLUTE(.);
+    _loader_text_start = ABSOLUTE(.);
     *(.stub .gnu.warning .gnu.linkonce.literal.* .gnu.linkonce.t.*.literal .gnu.linkonce.t.*)
      *(.iram1 .iram1.*) /* catch stray IRAM_ATTR */
     *liblog.a:(.literal .text .literal.* .text.*)
     *libgcc.a:(.literal .text .literal.* .text.*)
+    *libbootloader_support.a:bootloader_common.o(.literal .text .literal.* .text.*)
     *libbootloader_support.a:bootloader_flash.o(.literal .text .literal.* .text.*)
     *libbootloader_support.a:bootloader_random.o(.literal .text .literal.* .text.*)
     *libbootloader_support.a:bootloader_utility.o(.literal .text .literal.* .text.*)
@@ -56,7 +57,7 @@ SECTIONS
     *(.fini.literal)
     *(.fini)
     *(.gnu.version)
-    _text_end = ABSOLUTE(.);
+    _loader_text_end = ABSOLUTE(.);
     _etext = .;
   } > iram_loader_seg