mimxrt/hal/qspi_nor_flash_config: Use a safe common CS timing.

The flash devices used by the MIMXRT board are specified either with 3ns or
5 ns CS setup and hold time.  Since a single configuration file is used for
all boards, use 5ns instead of 3ns to be safe, even if there were no
problems so far.

Signed-off-by: robert-hh <robert@hammelrath.com>

Author: robert-hh

ports/mimxrt/hal/qspi_nor_flash_config.c

@@ -38,8 +38,8 @@ const flexspi_nor_config_t qspiflash_config = {
         .tag = FLEXSPI_CFG_BLK_TAG,
         .version = FLEXSPI_CFG_BLK_VERSION,
         .readSampleClkSrc = MICROPY_HW_FLASH_DQS,
-        .csHoldTime = 3u,
-        .csSetupTime = 3u,
+        .csHoldTime = 5u,   // safe time for all flash devices
+        .csSetupTime = 5u,
         .busyOffset = FLASH_BUSY_STATUS_OFFSET,         // Status bit 0 indicates busy.
         .busyBitPolarity = FLASH_BUSY_STATUS_POL,       // Busy when the bit is 1.
         .deviceModeCfgEnable = 1u,