Fix Matrix*x4_LoadIdentity (xash3d_mathlib.h) #2657

Job	Run time
flatpak (su.xash.Engine.Compat.i386)	3m 47s
build (ubuntu-20.04, linux, amd64)	3m 15s
build (ubuntu-20.04, linux, i386)	3m 37s
build (ubuntu-20.04, linux, arm64, true)	4m 24s
build (ubuntu-20.04, linux, armhf, true)	3m 43s
build (ubuntu-20.04, linux, riscv64, true)	3m 14s
build (ubuntu-20.04, linux, ppc64el, true)	3m 39s
build (ubuntu-20.04, android, multiarch)	11m 55s
build (ubuntu-latest, nswitch, arm64)	3m 24s
build (ubuntu-latest, psvita, armv7hf)	8m 9s
build (windows-latest, win32, amd64)	2m 57s
build (windows-2019, win32, i386)	3m 19s
build (macos-14, apple, arm64)	1m 46s
build (macos-13, apple, amd64)	3m 0s
Upload releases	0s
	1h 0m 9s

Provide feedback