Will MCUs oscillator accept 11.059 cristal?
The uC will accept any crystal >Fmin (typ 0 these days) and < F max.
How to use 12MHz crisal and internal UART? HOPE that the baudrate is close enough for the other end to communicate. If not, select a lower baudrate.

12 MHZ or whatever is the max frequency the uC will operate on. 11.0592 is one frequency that allow the UART to operate at the correct baudrate.
when selecting a crystal think UART not uC this, of course does no apply if you are not doing serail communications.

Erik