[rocm-libraries] ROCm/rocm-libraries#9011 (commit 481ed45)

docs(rocprim): update benchmark instructions

## Motivation

I had forgotten to update the `## Running benchmarks` section of
rocPRIM's readme, back when I created my PR [feat(rocprim): use
primbench in rocPRIM](ROCm/rocm-libraries#2687).

## Technical Details

See the `Files changed` tab of this PR.

## Test Plan

Check that the documentation renders correctly and that all added URLs
work.

## Test Result

The documentation [renders
correctly](https://github.com/ROCm/rocm-libraries/blob/users/mynameistrez/update-benchmark-instructions/projects/rocprim/README.md#running-benchmarks),
and I checked that the added URLs redirect to the correct page when
clicked.

## Submission Checklist

- [x] Look over the contributing guidelines at
https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

Closes #9012

Author: MyNameIsTrez

README.md

@@ -247,24 +247,16 @@ static constexpr unsigned int seeds [] = {};
 
 ## Running benchmarks
 
+rocPRIM uses [primbench](https://github.com/ROCm/rocm-libraries/tree/develop/shared/primbench) for benchmarking; see its [command-line options](https://github.com/ROCm/rocm-libraries/tree/develop/shared/primbench#command-line-options).
+
 ```shell
 # Go to rocPRIM build directory
 cd rocPRIM; cd build
 
-# To run benchmark for warp functions:
-# Further option can be found using --help
-# [] Fields are optional
-./benchmark/benchmark_warp_<function_name> [--size <size>] [--trials <trials>]
-
-# To run benchmark for block functions:
-# Further option can be found using --help
-# [] Fields are optional
-./benchmark/benchmark_block_<function_name> [--size <size>] [--trials <trials>]
-
-# To run benchmark for device functions:
-# Further option can be found using --help
-# [] Fields are optional
-./benchmark/benchmark_device_<function_name> [--size <size>] [--trials <trials>]
+# To run benchmarks for warp, block, or device functions:
+./benchmark/benchmark_warp_<function_name>
+./benchmark/benchmark_block_<function_name>
+./benchmark/benchmark_device_<function_name>
 ```
 
 ### Performance configuration