MLK-21060 i2c: lpi2c: Fix clk fetch

During porting commit ede264ac ("MLK-14982-1 imx8: lpi2c: add ipg
clk for lpi2c driver") which replaced the single clk
with clk_ipg and clk_per was skipped.

Part of the code was later added in commit 96dbdd8c3d0b ("MLK-16713 i2c:
imx-lpi2c: add runtime pm support") except the "clk" field was kept and
clk_get calls were not updated.

Fix imx7ulp boot by fetching both clocks.

Fixes: 96dbdd8c3d0b ("MLK-16713 i2c: imx-lpi2c: add runtime pm support")

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Acked-by: Fugang Duan <fugang.duan@nxp.com>