riscv: compat: fix COMPAT_UTS_MACHINE definition

riscv: compat: fix COMPAT_UTS_MACHINE definition

The COMPAT_UTS_MACHINE for riscv was incorrectly defined as "riscv".
Change it to "riscv32" to reflect the correct 32-bit compat name.

Fixes: 06d0e3723647 ("riscv: compat: Add basic compat data type implementation")
Cc: stable@vger.kernel.org
Signed-off-by: Han Gao <gaohan@iscas.ac.cn>
Reviewed-by: Guo Ren (Alibaba Damo Academy) <guoren@kernel.org>
Link: https://patch.msgid.link/20260127190711.2264664-1-gaohan@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>