reset: thead: Fix TH1520 typo

Fix trivial typo in the Kconfig entry for RESET_TH1520.

Fixes: 4a653263 ("reset: thead: Add TH1520 reset controller driver")
Signed-off-by: Drew Fustini <drew@pdp7.com>
Link: https://lore.kernel.org/r/20250601181000.166088-1-drew@pdp7.com


Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>