clk: fix clk_get_bulk when phandle error
This fixes the Coverity Defect CID 175347 when dev_count_phandle_with_args()
returns a negative value.
Fixes: a855be87da49 ("clk: Add get/enable/disable/release for a bulk of clocks")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>