CLSA-2023-1674815966 grub2: Fix of 2 CVEs

font: Reject glyphs exceeds font-maxglyphwidth or font-maxglyph height - font: Fix size overflow in grubfontgetglyphinternal - CVE-2022-2601: font: Fix several integer overflows in grubfontconstructglyph - CVE-2022-3775: font: Fix an integer underflow in blitcomb...