[libpng] Fix libpng for android

[m-kuhn]

Describe the problem

check is only a valid value for arm architectures.

On arm64 this errors with

CMake Error at CMakeLists.txt:108 (message):
  PNG_ARM_NEON must be one of [on;off]

Describe the pull request

Only use check on arm

[Cheney-W]

The failures on CI are known and they are being fixed.

The default is on (with neon) which is the only configuration accepted by the latest ndk r25 which has dropped support for non neon devices.

Is this only implemented on top of the latest? So if it's not the latest, will your changes cause other errors?

[m-kuhn]

Digging deeper... The upstream logic actually has a dependency on the target architecture:

https://github.com/glennrp/libpng/blob/libpng16/CMakeLists.txt#L95-L104

This should be updated to switch to check if VCPKG_TARGET_ARCHITECTURE STREQUAL "arm".

[dg0yt]

FTR a similar PR was reviewed in #27936.

[Cheney-W]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[m-kuhn]

Should be fine now

[JavierMatosD]

Thank you!