Add cstdint header to resolve build issue with gcc-15

[yktyagi]

Following build issue is observed when building libvpl-tools in yocto project with gcc-15

| /poky_master/build/tmp/work/corei7-64-poky-linux/libvpl-tools/1.4.0/git/tools/legacy/sample_vpp/src/sample_vpp_frc_adv.cpp: In member function 'virtual mfxStatus FRCAdvancedChecker::Init(mfxVideoParam*, mfxU32)':
| /poky_master/build/tmp/work/corei7-64-poky-linux/libvpl-tools/1.4.0/git/tools/legacy/sample_vpp/src/sample_vpp_frc_adv.cpp:60:11: error: 'uint64_t' was not declared in this scope
| 60 | ((uint64_t)m_videoParam.vpp.In.FrameRateExtD * (uint64_t)MFX_TIME_STAMP_FREQUENCY) /
| | ^~~~~~~~
| /poky_master/build/tmp/work/corei7-64-poky-linux/libvpl-tools/1.4.0/git/tools/legacy/sample_vpp/src/sample_vpp_frc_adv.cpp:11:1: note: 'uint64_t' is defined in header ''; this is probably fixable by adding '#include '
| 10 | #include "vm/strings_defs.h"
| +++ |+#include
| 11 |
| /poky_master/build/tmp/work/corei7-64-poky-linux/libvpl-tools/1.4.0/git/tools/legacy/sample_vpp/src/sample_vpp_frc_adv.cpp:60:20: error: expected ')' before 'm_videoParam'
| 60 | ((uint64_t)m_videoParam.vpp.In.FrameRateExtD * (uint64_t)MFX_TIME_STAMP_FREQUENCY) /
| | ~ ^~~~~~~~~~~~
| | )

[Nowa-Ammerlaan]

Works for me, backporting into Gentoo.

[jonrecker]

Thank you for the PR. Your commit has been cherry-picked into the closed-source mirror of this repo for validation, and it will be pushed back to this repo (github.com/intel/libvpl-tools) as part of the next release. We will leave this PR open for now so that the status can be tracked.