tools/x86/kcpuid: Strip bitfield names leading/trailing whitespace

While parsing and saving bitfield names from the CSV file, an extra
leading space is copied verbatim.  That extra space is not a big issue
now, but further commits will add a new CSV file with much more padding
for the bitfield's name column.

Strip leading/trailing whitespaces while saving bitfield names.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-6-darwi@linutronix.de