refactor(libntfs-3g): optimise ntfs_uppercase_mbs

[safocl]

fix multiple checking and ptr increments

the following lines do a double check of the same for every cycle:

ntfs-3g/libntfs-3g/unistr.c

Line 1167 in 75dcdc2

if (n > 0) {

and

ntfs-3g/libntfs-3g/unistr.c

Line 1187 in 75dcdc2

} while (n > 0);

(double checks of (n > 0)

the lines with *t++ = [...] perform multiple increments.

[safocl]

(wc < 0x80)
(wc < 0x800)
(wc < 0x10000)
maybe replace with (n == {1, 2, 3}) ?

ntfs-3g/libntfs-3g/unistr.c

Line 1166 in 75dcdc2

n = utf8_to_unicode(&wc, s);

ntfs-3g/libntfs-3g/unistr.c

Line 741 in 75dcdc2

* Return the number of used utf8 bytes or -1 with errno set