"arm64: vdso: Substitute gettimeofday() with C implementation" breaks clang build

[Qian Cai]

The linux-next commit "arm64: vdso: Substitute gettimeofday() with C
implementation" [1] breaks clang build.

error: invalid value 'tiny' in '-mcode-model tiny'
make[1]: *** [scripts/Makefile.build:279:
arch/arm64/kernel/vdso/vgettimeofday.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [arch/arm64/Makefile:180: vdso_prepare] Error 2

[1] https://patchwork.kernel.org/patch/11009663/