i2c: designware: use casting of u64 in clock multiplication to avoid overflow

In the Linux kernel, the following vulnerability has been resolved:

i2c: designware: use casting of u64 in clock multiplication to avoid overflow

In functions i2c_dw_scl_lcnt() and i2c_dw_scl_hcnt() may have overflow
by depending on the values of the given parameters including the ic_clk.
For example in our use case where ic_clk is larger than one million,
multiplication of ic_clk * 4700 will result in 32 bit overflow.

Add cast of u64 to the calculation to avoid multiplication overflow, and
use the corresponding define for divide.