efi_loader: updating the cursor position

efi_loader: updating the cursor position

The current coding advances the column by the number of UTF-8 bytes.
The column should be increased by one per unicode character.

The UEFI spec provides advance rules for U+0000, U+0008, U+000A,
and U000D. All other characters, including control characters
U+0007 (bel) and U+0009 (tab), have to increase the column by one.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>