kernel.nix: boot.vesa implies nomodeset

Without nomodeset the console is reset to 80x25 after Grub

nixos/modules/system/boot/kernel.nix

@@ -196,7 +196,7 @@ in
     # (so you don't need to reboot to have changes take effect).
     boot.kernelParams =
       [ "loglevel=${toString config.boot.consoleLogLevel}" ] ++
-      optionals config.boot.vesa [ "vga=0x317" ];
+      optionals config.boot.vesa [ "vga=0x317" "nomodeset" ];
 
     boot.kernel.sysctl."kernel.printk" = mkDefault config.boot.consoleLogLevel;