configs/*/grub/grub.cfg: rearrange module loading

* Do not manually load modules that will get loaded by invoking a command.
* Explicitly load serial modules.
* Move `insmod all_video` after the font is loaded.

grub/grub.cfg

@@ -9,15 +9,19 @@ insmod exfat
 insmod udf
 
 # Use graphics-mode output
-insmod all_video
-insmod font
 if loadfont "${prefix}/fonts/unicode.pf2" ; then
+    insmod all_video
     set gfxmode="auto"
     terminal_input console
     terminal_output console
 fi
 
 # Enable serial console
+insmod serial
+insmod usbserial_common
+insmod usbserial_ftdi
+insmod usbserial_pl2303
+insmod usbserial_usbdebug
 if serial --unit=0 --speed=115200; then
     terminal_input --append serial
     terminal_output --append serial
@@ -61,12 +65,10 @@ if [ "${grub_platform}" == "efi" ]; then
             linux /boot/memtest86+/memtest.efi
         }
         menuentry "UEFI Shell" --class efi {
-            insmod chain
             chainloader /shellx64.efi
         }
     elif [ "${grub_cpu}" == "i386" ]; then
         menuentry "UEFI Shell" --class efi {
-            insmod chain
             chainloader /shellia32.efi
         }
     fi