spi: fix the crash when callbacks are not in the IRAM

Introduced in 9c23b8e5 and 4f87a62f. To get higher speed, menuconfig
options are added to put ISR and other functions into the IRAM.  The
interrupt flag ESP_INTR_FLAG_IRAM is also mistakenly set when the ISR is
put into the IRAM. However callbacks, which are wrote by the user, are
called in the master and slave ISR. The user may not be aware of that
these callbacks are not disabled during flash operations. Any cache miss
during flash operation will cause panic.

Essentially IRAM functions and intrrupt flag ESP_INTR_FLAG_IRAM are
different, the latter means not disabling the ISR during flash
operations.  New bus_config flag intr_flags is offered to help set the
interrupt attribute, including priority level, SHARED, IRAM (not
disabled during flash operations).  It introduced a small BREAK to
IDFv3.1 (but the same as IDFv3.0) that the user has to manually set IRAM
flag now (therefore he's aware of the IRAM thing) to void the ISR being
disabled during flash operations.

components/driver/include/driver/spi_common.h

@@ -87,6 +87,11 @@ typedef struct {
     int quadhd_io_num;              ///< GPIO pin for HD (HolD) signal which is used as D3 in 4-bit communication modes, or -1 if not used.
     int max_transfer_sz;            ///< Maximum transfer size, in bytes. Defaults to 4094 if 0.
     uint32_t flags;                 ///< Abilities of bus to be checked by the driver. Or-ed value of ``SPICOMMON_BUSFLAG_*`` flags.
+    int intr_flags;    /**< Interrupt flag for the bus to set the priority, and IRAM attribute, see
+                         *  ``esp_intr_alloc.h``. Note that the EDGE, INTRDISABLED attribute are ignored
+                         *  by the driver. Note that if ESP_INTR_FLAG_IRAM is set, ALL the callbacks of
+                         *  the driver, and their callee functions, should be put in the IRAM.
+                         */
 } spi_bus_config_t;