LoongArch: uprobes: Remove user_{en,dis}able_single_step()

LoongArch: uprobes: Remove user_{en,dis}able_single_step()

commit 0b326b2371f94e798137cc1a3c5c2eef2bc69061 upstream.

When executing the "perf probe" and "perf stat" test cases about some
cryptographic algorithm, the output shows that "Trace/breakpoint trap".
This is because it uses the software singlestep breakpoint for uprobes
on LoongArch, and no need to use the hardware singlestep. So just remove
the related function call to user_{en,dis}able_single_step() for uprobes
on LoongArch.

How to reproduce:

Please make sure CONFIG_UPROBE_EVENTS is set and openssl supports sm2
algorithm, then execute the following command.

cd tools/perf && make
./perf probe -x /usr/lib64/libcrypto.so BN_mod_mul_montgomery
./perf stat -e probe_libcrypto:BN_mod_mul_montgomery openssl speed sm2

Cc: stable@vger.kernel.org
Fixes: 19bc6cb64092 ("LoongArch: Add uprobes support")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>