Fix pin ordering for pins with names in pio_spi_flash

[will-v-pi]

bi_4pins_with_names does not have any ordering as it's a pin mask, so the pins must be in order, which cannot be guaranteed here depending on the default pins. This causes the names to appear next to the wrong pins in picotool info

Eg for pico, with

#define PICO_DEFAULT_SPI_SCK_PIN 18
#define PICO_DEFAULT_SPI_TX_PIN 19
#define PICO_DEFAULT_SPI_RX_PIN 16
#define PICO_DEFAULT_SPI_CSN_PIN 17

picotool info -p shows

16:  SPI RX
17:  SPI TX
18:  SPI SCK
19:  SPI CS

This will throw a compilation error once pico-sdk/#1791 is merged, so this should be merged before that

Switch to 4 spearate bi_1pin_with_name to ensure the right name matches the right pin