sparc: add _image_rodata_start/end to linker script

This adds the _image_rodata_start and _image_rodata_end
symbols to SPARC's arch linker script.

Signed-off-by: Daniel Leung <[email protected]>

Author: dcpleung

include/arch/sparc/linker.ld

@@ -40,6 +40,7 @@ SECTIONS
 	} GROUP_LINK_IN(REGION_TEXT)
 
     _image_text_end = .;
+    _image_rodata_start = .;
 
 #include <linker/common-rom.ld>
 #include <linker/thread-local-storage.ld>
@@ -61,7 +62,11 @@ SECTIONS
 
 #include <linker/cplusplus-rom.ld>
 
+    _image_rodata_end = .;
+    _image_rodata_size = _image_rodata_end - _image_rodata_start;
+
     _image_rom_end = .;
+
     __data_rom_start = .;