This patch alone is not sufficient.  You also need to add a case for
1200Hz to the switch table at:

                 * When the CPU clock oscillator frequency is not a
                 * power of 2 in Hz, shifthz is only an approximate
		 ...

I.e.:
		case 1200:
			/* A factor of 1.1011 gives about .011% error. */
			if (time_adj < 0) {
				time_adj -= (-time_adj >> 1);
				time_adj -= (-time_adj >> 3);
			} else {
				time_adj += (time_adj >> 1);
				time_adj += (time_adj >> 3);
			}
			break;