Merge pull request #24305 from hanliutong:toolchain

cmake: Fix riscv-gnu toolchain file. #24305

cmake(3.22.1) failed without the keyword `PATHS` on my device when I manually set `TOOLCHAIN_COMPILER_LOCATION_HINT` in command. And this patch is going to fix this issue.

[CMake Doc](https://cmake.org/cmake/help/latest/command/find_program.html):
> find_program (
>           <VAR>
>           name | NAMES name1 [name2 ...] [NAMES_PER_DIR]
>           [HINTS [path | ENV var]... ]
>           [PATHS [path | ENV var]... ]

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [ ] I agree to contribute to the project under Apache 2 License.
- [ ] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

platforms/linux/riscv-gnu.toolchain.cmake

@@ -25,22 +25,22 @@ if(NOT DEFINED TOOLCHAIN_COMPILER_LOCATION_HINT)
 endif()
 
 if(NOT DEFINED CMAKE_C_COMPILER)
-  find_program(CMAKE_C_COMPILER NAMES ${GNU_MACHINE}-gcc${__GCC_VER_SUFFIX} ${TOOLCHAIN_COMPILER_LOCATION_HINT})
+  find_program(CMAKE_C_COMPILER NAMES ${GNU_MACHINE}-gcc${__GCC_VER_SUFFIX} PATHS ${TOOLCHAIN_COMPILER_LOCATION_HINT})
 else()
   #message(WARNING "CMAKE_C_COMPILER=${CMAKE_C_COMPILER} is defined")
 endif()
 if(NOT DEFINED CMAKE_CXX_COMPILER)
-  find_program(CMAKE_CXX_COMPILER NAMES ${GNU_MACHINE}-g++${__GCC_VER_SUFFIX} ${TOOLCHAIN_COMPILER_LOCATION_HINT})
+  find_program(CMAKE_CXX_COMPILER NAMES ${GNU_MACHINE}-g++${__GCC_VER_SUFFIX} PATHS ${TOOLCHAIN_COMPILER_LOCATION_HINT})
 else()
   #message(WARNING "CMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER} is defined")
 endif()
 if(NOT DEFINED CMAKE_LINKER)
-  find_program(CMAKE_LINKER NAMES ${GNU_MACHINE}-ld${__GCC_VER_SUFFIX} ${GNU_MACHINE}-ld ${TOOLCHAIN_COMPILER_LOCATION_HINT})
+  find_program(CMAKE_LINKER NAMES ${GNU_MACHINE}-ld${__GCC_VER_SUFFIX} ${GNU_MACHINE}-ld PATHS ${TOOLCHAIN_COMPILER_LOCATION_HINT})
 else()
   #message(WARNING "CMAKE_LINKER=${CMAKE_LINKER} is defined")
 endif()
 if(NOT DEFINED CMAKE_AR)
-  find_program(CMAKE_AR NAMES ${GNU_MACHINE}-ar${__GCC_VER_SUFFIX} ${GNU_MACHINE}-ar ${TOOLCHAIN_COMPILER_LOCATION_HINT})
+  find_program(CMAKE_AR NAMES ${GNU_MACHINE}-ar${__GCC_VER_SUFFIX} ${GNU_MACHINE}-ar PATHS ${TOOLCHAIN_COMPILER_LOCATION_HINT})
 else()
   #message(WARNING "CMAKE_AR=${CMAKE_AR} is defined")
 endif()