Fix ClangTidy misc-include-cleaner warnings

Include headers to fix the following ClangTidy misc-include-cleaner warnings:

src/cpu.c: no header providing "errno" is directly included no header providing "ENOSYS" is directly included

src/looprestoration_tmpl.c: no header providing "int32_t" is directly included no header providing "coef" is directly included no header providing "ALIGN_STK_16" is directly included no header providing "HIGHBD_TAIL_SUFFIX" is directly included no header providing "BITDEPTH_MAX" is directly included

See https://clang.llvm.org/extra/clang-tidy/checks/misc/include-cleaner.html.