gencontrol: s/initramfs-tools/update-initramfs/

The current implementation conflates the "update-initramfs" executable name with the "initramfs-tools" package name. However, initramfs-tools is not the only package to provide update-initramfs, so the naming is unfortunate and can lead to confusion.

Rename the occurences of "initramfs-tools" to "update-initramfs" to better convey the idea that the template is used for the update-initramfs dpkg trigger and does not strictly depend on initramfs-tools.

Closes: #1135723 Signed-off-by: Agathe Porte agathe.porte@oss.qualcomm.com