scale.c: Use int instead of kernel_t for values in named_int_t

scale.c: Use int instead of kernel_t for values in named_int_t

The 'value' field in the 'named_int_t' struct is used for both
pixman_repeat_t and pixman_kernel_t values, so the type should be int,
not pixman_kernel_t.

Fixes some warnings like this

scale.c:124:33: warning: implicit conversion from enumeration
      type 'pixman_repeat_t' to different enumeration type
      'pixman_kernel_t' [-Wconversion]
    { "None",                   PIXMAN_REPEAT_NONE },
    ~                           ^~~~~~~~~~~~~~~~~~

when compiled with clang.