clk: highbank: Remove an unused field in struct hb_clk

In "struct hb_clk", the 'parent_name' field is unused.

Remove it.

Found with cppcheck, unusedStructMember.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/90b19f2af3077075d4254e01d5ae919c423d067e.1713016457.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Stephen Boyd <sboyd@kernel.org>