sw64: remove single step setting in uprobe

Sunway inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5XTMN



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There is no point in calling user_{enable,disable}_single_step()
since uprobe breakpoints are implemented by illegal instructions
on sw64.

The arch-specific implementation of these two functions have been
removed before, and it's time to remove the calling now.

Signed-off-by: He Chuyue <hechuyue@wxiat.com>
Reviewed-by: He Sheng <hesheng@wxiat.com>
Signed-off-by: Gu Zitao <guzitao@wxiat.com>