r600: add missing <array> include

r600: add missing <array> include

Fixes error with clang/libc++:

../src/gallium/drivers/r600/sfn/sfn_emitaluinstruction.h:69:88: error: implicit instantiation of undefined template 'std::__1::array<unsigned char, 3>'
   bool emit_alu_op3(const nir_alu_instr& instr, EAluOp opcode, std::array<uint8_t, 3> reorder={0,1,2});

Reviewed-by: Gert Wollny <gert.wollny@collabora.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3967>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3967>