kernel: clk: Fix clk_core_get NULL dereference

In the Linux kernel, the following vulnerability has been resolved: clk: Fix clkcoreget NULL dereference It is possible for clkcoreget to dereference a NULL in the following sequence: clkcoreget ofclkgethwfromclkspec ofclkgethwfromprovider clkgethw clkgethw can return NULL which is dereferenced b...