clk: nxp: clk-lpc32xx: Unmap region obtained by of_iomap

Free memory mapping, if lpc32xx_clk_init is not successful.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Sylvain Lemieux <slemieux.tyco@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>