[RISCV] Allow mismatched SmallDataLimit and use Min for conflicting values

Fix an issue about module linking with LTO.

When compiling with PIE, the small data limitation needs to be consistent with that in PIC, otherwise there will be linking errors due to conflicting values.

bar.c
```
int bar() { return 1; }
```

foo.c
```
int foo() { return 1; }
```

```
clang --target=riscv64-unknown-linux-gnu -flto -c foo.c -o foo.o -fPIE
clang --target=riscv64-unknown-linux-gnu -flto -c bar.c -o bar.o -fPIC

clang --target=riscv64-unknown-linux-gnu -flto foo.o bar.o -flto -nostdlib -v -fuse-ld=lld
```

```
ld.lld: error: linking module flags 'SmallDataLimit': IDs have conflicting values in 'bar.o' and 'ld-temp.o'
clang-15: error: linker command failed with exit code 1 (use -v to see invocation)
```

Use Min instead of Error for conflicting SmallDataLimit.

Authored by: @joshua-arch1
Signed-off-by: xiaojing.zhang <xiaojing.zhang@xcalibyte.com>
Signed-off-by: jianxin.lai <jianxin.lai@xcalibyte.com>

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D131230