Print boot mode at info log level

This commit logs either "Configuring VM for Linux boot." or
"Configuring VM for PVH boot." at the "info" log level, in order
to make it easier to see which boot mode is being used.

Requested by: pb8o
Signed-off-by: Colin Percival <cperciva@freebsd.org>

Author: cperciva

src/vmm/src/arch/x86_64/mod.rs

@@ -27,6 +27,7 @@ use linux_loader::loader::bootparam::boot_params;
 use linux_loader::loader::elf::start_info::{
     hvm_memmap_table_entry, hvm_modlist_entry, hvm_start_info,
 };
+use log::info;
 use utils::vm_memory::{Address, GuestAddress, GuestMemory, GuestMemoryMmap, GuestMemoryRegion};
 
 use super::BootProtocol;
@@ -130,9 +131,11 @@ pub fn configure_system(
 
     match boot_prot {
         BootProtocol::PvhBoot => {
+            info!("Configuring VM for PVH boot.");
             configure_pvh(guest_mem, cmdline_addr, initrd)?;
         }
         BootProtocol::LinuxBoot => {
+            info!("Configuring VM for Linux boot.");
             configure_64bit_boot(guest_mem, cmdline_addr, cmdline_size, initrd)?;
         }
     }