Correct clipping in sceFontGetCharGlyphImage_Clip.

It was not clipping completely, and didn't handle negative clip w/h.
Also, reduce to debug log (seems to work fine now and has been working
fine in most games.)
Get rid of Memory::GetStruct(), use PSPPointer.
Merge pull request #5577 from unknownbrackets/font

Correct clipping in sceFontGetCharGlyphImage_Clip()