Revert "Fonts: Make font size unsigned in font_desc"

This reverts commit 78e008dc which is
commit 7cb41500 upstream.

It breaks the Android kernel ABI and is not needed for Android devices,
so it is safe to revert for now.  If it is determined that it is needed
in the future, it can be brought back in an abi-preserving way.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I6070f402034c1d22ea70db2d1be160b0d0270b8e