[PATCH v3 04/14] MFD: twl-core: Add API to query the HFCLK rate

CFG_BOOT register's HFCLK_FREQ field hold information about the used HFCLK frequency. Add possibility for users to get the configured rate based on this register. This register was configured during boot, without it the chip would not operate correctly, so we can trust on this information.

[PATCH v3 04/14] MFD: twl-core: Add API to query the HFCLK rate

CFG_BOOT register's HFCLK_FREQ field hold information about the used HFCLK frequency. Add possibility for users to get the configured rate based on this register. This register was configured during boot, without it the chip would not operate correctly, so we can trust on this information.