Log discovered base address

Note the base address that is going into created kernel elf.  Seeing the
actual address can help determine if something wonky is going on.

vmlinux_to_elf/elf_symbolizer.py

@@ -77,10 +77,13 @@ def __init__(self, file_contents : bytes, output_file : str,
 
             if base_address is not None:
                 progbits.section_header.sh_addr = base_address
+                logging.info(f"[+] Explicit base address given ({progbits.section_header.sh_addr:x})")
             elif kallsyms_finder.kernel_text_candidate:
                 progbits.section_header.sh_addr = kallsyms_finder.kernel_text_candidate
+                logging.info(f"[+] Base address using kernel_text_candidate ({progbits.section_header.sh_addr:x})")
             else:
                 progbits.section_header.sh_addr = first_symbol_virtual_address & 0xfffffffffffff000
+                logging.info(f"[+] Base address fallback, using first_symbol_virtual_address ({progbits.section_header.sh_addr:x})")
 
             progbits.section_contents = file_contents