In 'struct lp50xx_led', the 'bank_modules' field is unused. Remove it.

Found with cppcheck, unusedStructMember.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/bc2e5e57b93ca0a33bcc84e9bdc89f26fc8f6d57.1714324500.git.christophe.jaillet@wanadoo.frSigned-off-by: Lee Jones <lee@kernel.org>