flashrom

For RC1, we can add a paragraph into README, into "Build Instructions" section.
The paragraph should mention we have meson build system (not fully ready for all the environments), people are welcome to use meson and link to the instructions: /Documentation/building.md

https://review.coreboot.org/c/flashrom/+/70176

Just for reference, the ChromiumOS fork of flashrom, with its additional specialized references to the ChromiumOS Write Protect functions, can no longer be built with the make build system, simply because Google has declined to update their version of the upstream Makefile, and now relies exclusively on the meson build system. The ChromiumOS flashrom Makefile will fail to build flashchips_crosbl.c, action_descriptor.c, cros_ec.c, and power.c, resulting ultimately in undefined function references. Google anticipates that the make build system will be removed from upstream flashrom in the future, and then also has declined to update the ChromiumOS fork flashrom README reference to "flashrom supports building with make and meson", which, then, becomes misleading and no longer true for ChromiumOS flashrom.