Update build_style for all templates.

- There's no need to set build_style for custom-install (default).
- gnu_{configure,makefile} renamed to gnu-{configure,makefile}.

srcpkgs/linux-firmware/template

@@ -1,7 +1,6 @@
 # Template file for 'linux-firmware'
 pkgname=linux-firmware
 version="$(date -u +%Y%m%d)"
-build_style=custom-install
 short_desc="Binary firmware blobs for the Linux kernel"
 maintainer="Juan RP <xtraeme@gmail.com>"
 homepage="http://www.kernel.org/"