xtensa: add build support for AMD/Phoenix #43

Job	Run time
crosstool (ubuntu-latest)	3m 55s
toolchains (ubuntu-latest, aarch64-unknown-linux-gnu)	55m 32s
toolchains (ubuntu-latest, arc-multilib-linux-uclibc)	43m 0s
toolchains (ubuntu-latest, arm-picolibc-eabi)	1h 22m 29s
toolchains (ubuntu-latest, arm-unknown-linux-gnueabi)	1h 4m 19s
toolchains (ubuntu-latest, armv6-nommu-linux-uclibcgnueabi)	46m 18s
toolchains (ubuntu-latest, mips-unknown-elf)	22m 49s
toolchains (ubuntu-latest, mips64-unknown-linux-gnu)	52m 14s
toolchains (ubuntu-latest, powerpc-unknown-linux-gnu)	58m 32s
toolchains (ubuntu-latest, powerpc64-unknown-linux-gnu)	59m 45s
toolchains (ubuntu-latest, riscv32-unknown-elf)	15m 40s
toolchains (ubuntu-latest, riscv64-unknown-elf)	28m 58s
toolchains (ubuntu-latest, s390-unknown-linux-gnu)	56m 20s
toolchains (ubuntu-latest, sh-multilib-linux-gnu)	1h 48m 58s
toolchains (ubuntu-latest, sparc-unknown-linux-gnu)	39m 43s
toolchains (ubuntu-latest, x86_64-unknown-linux-gnu)	59m 29s
toolchains (ubuntu-latest, x86_64-multilib-linux-uclibc)	59m 53s
toolchains (ubuntu-latest, xtensa-fsf-linux-uclibc)	51m 29s
	15h 9m 23s

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