In recent years the Itanium support in the Linux kernel has went downhill with not many users left testing new kernels on aging Itanium servers. There also hasn't been any major active contributors to the Itanium code for keeping it maintained and making any serious improvements to the architecture code. On and off for months there's been talk of retiring Itanium from the Linux kernel and now it's finally happened.
With Linux 6.6 expected to be this year's Long-Term Support (LTS) kernel version, there was the proposal recently to drop Itanium in Linux 6.7 and indeed it's successfully happened.
Due to the IA-64 kernel code being unmaintained and no one willing to step up to keep it going, the 65k lines of code for supporting it have been removed.
The asm-generic pull cleared out all of the IA-64 architecture support for a "well-earned retirement." Anyone still with IA-64 hardware around will want to stick to Linux 6.6 LTS.
Farewell, Itanium!