sm8250 devices improve: use losetup and fix qbootctl

[amazingfate]

Description

• Ubuntu noble ships qbootctl with a bug which makes qbootctl service can't start: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1057918. I fixed it in my ppa liujianfeng1994/qcom-mainline.
• I use a silly dd method to create rootfs. It's better to use losetup to load the built image and copy rootfs from the mounted loop device.

Note: ubuntu noble also ships mkbootimg with bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1050300, which will make this extension not working. So it's better not using noble as build environment. Debian's fix is still not packaged: https://salsa.debian.org/android-tools-team/android-platform-tools/-/commit/d26c3b5ac89efd92eb96ad029cd06400c1c9f015

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• ./compile.sh BOARD=xiaomi-elish BRANCH=current BUILD_DESKTOP=yes BUILD_MINIMAL=no DEB_COMPRESS=xz DESKTOP_APPGROUPS_SELECTED= DESKTOP_ENVIRONMENT=gnome DESKTOP_ENVIRONMENT_CONFIG_NAME=config_base KERNEL_CONFIGURE=no KERNEL_GIT=shallow RELEASE=noble

Checklist:

Please delete options that are not relevant.

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules