main/postmarketos-mkinitfs: Include ext4 and usb_f_rndis in initramfs

(see commit message)

This fixes mounting the rootfs and USB network if those are built as modules instead of built-in.

device/device-surftab-wintron7.0/APKBUILD

@@ -2,7 +2,7 @@
 pkgname="device-surftab-wintron7.0"
 pkgdesc="TrekStor SurfTab wintron 7.0"
 pkgver=0.3
-pkgrel=1
+pkgrel=2
 url="https://postmarketos.org"
 license="MIT"
 arch="x86_64"
@@ -32,5 +32,5 @@ nonfree_firmware() {
 	mkdir "$subpkgdir"
 }
 
-sha512sums="1dc0d206905aad9de0efc7284bdb8b27f739d0657d848a616c7df89a7bd982c579a492590e1413a88c772d81d5222847c683bbb8ecdcfb410e31bd9e568bc5fb  deviceinfo
+sha512sums="27c4941de46973dace7147fd65ceb447fde36e5b1350f5db2296de9ef8c68cce24580c9391f805b9b919679f66ad01c9c70826da6ffe3506870ec2ccbd5d8fee  deviceinfo
 8b77755eb59c07f84cb00439f09e0f4bbc2fdf6da8e41160bb1967463c0e098d012a18465891a5d0fc64a37712ba3840a110aa7a371da90c23b4fcd7ac63c004  grub.cfg"