[nrf fromlist] drivers: spi: nrfx_spim: Add support for non standard frequencies

Disabled frequency set approximation algorithm for spim's with prescaler.

Upstream PR: #92436

Signed-off-by: Michal Frankiewicz <[email protected]>

Author: mif1-nordic

drivers/spi/spi_nrfx_spim.c

@@ -172,9 +172,12 @@ static inline uint32_t get_nrf_spim_frequency(uint32_t frequency)
 {
 	/* Get the highest supported frequency not exceeding the requested one.
 	 */
-	if (frequency >= MHZ(32) && (NRF_SPIM_HAS_32_MHZ_FREQ || NRF_SPIM_HAS_PRESCALER)) {
+#if (NRF_SPIM_HAS_PRESCALER)
+	return frequency;
+#else
+	if (frequency >= MHZ(32) && NRF_SPIM_HAS_32_MHZ_FREQ) {
 		return MHZ(32);
-	} else if (frequency >= MHZ(16) && (NRF_SPIM_HAS_16_MHZ_FREQ || NRF_SPIM_HAS_PRESCALER)) {
+	} else if (frequency >= MHZ(16) && NRF_SPIM_HAS_16_MHZ_FREQ) {
 		return MHZ(16);
 	} else if (frequency >= MHZ(8)) {
 		return MHZ(8);
@@ -191,6 +194,7 @@ static inline uint32_t get_nrf_spim_frequency(uint32_t frequency)
 	} else {
 		return KHZ(125);
 	}
+#endif /* NRF_SPIM_HAS_PRESCALER */
 }
 
 static inline nrf_spim_mode_t get_nrf_spim_mode(uint16_t operation)