clk: mmp: Off by one in mmp_clk_add()

The > comparison should be >= or we write one element beyond the end of
the unit->clk_table[] array.

(The unit->clk_table[] array is allocated in the mmp_clk_init() function
and it has unit->nr_clks elements).

Fixes: 4661fda1 ("clk: mmp: add basic support functions for DT support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>