fix(sdmmc): Fix iomux pin initialization

[P-R-O-C-H-Y]

Description of Change

This pull request updates the SDMMC slot configuration for ESP32P4 boards to improve compatibility with ESP-IDF's pin checking logic. Instead of using GPIO_NUM_NC (-1), the code now sets all SDMMC pins to GPIO_NUM_0 (0), which works correctly with the ESP-IDF's s_check_pin_not_set() function.

Hardware compatibility fix:

• In SD_MMC.cpp, the SDMMC slot configuration for ESP32P4 boards now sets all pins (clk, cmd, d0–d7) to GPIO_NUM_0 instead of GPIO_NUM_NC, ensuring proper operation with ESP-IDF's pin validation logic.

Test Scenarios

Tested using P4 and SDMMC example.

Related links

Closes #11995

[github-actions]

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Generated by 🚫 dangerJS against 4868262

[github-actions]

Memory usage test (comparing PR against master branch)

The table below shows the summary of memory usage change (decrease - increase) in bytes and percentage for each target.

Memory	FLASH [bytes]		FLASH [%]		RAM [bytes]		RAM [%]
Target	DEC	INC	DEC	INC	DEC	INC	DEC	INC
ESP32P4	0	0	0.00	0.00	0	0	0.00	0.00
ESP32S3	0	0	0.00	0.00	0	0	0.00	0.00
ESP32	0	0	0.00	0.00	0	0	0.00	0.00

Click to expand the detailed deltas report [usage change in BYTES]

Target	ESP32P4		ESP32S3		ESP32
Example	FLASH	RAM	FLASH	RAM	FLASH	RAM
libraries/ESP_I2S/examples/Record_to_WAV	0	0	0	0	0	0
libraries/SD_MMC/examples/SD2USBMSC	0	0	0	0	-	-
libraries/SD_MMC/examples/SDMMC_Test	0	0	0	0	0	0
libraries/SD_MMC/examples/SDMMC_time	0	0	0	0	0	0

[SuGlider]

LGTM

[github-actions]

Test Results

 76 files   76 suites   16m 38s ⏱️
 38 tests  38 ✅ 0 💤 0 ❌
241 runs  241 ✅ 0 💤 0 ❌

Results for commit 4868262.

♻️ This comment has been updated with latest results.

[me-no-dev]

I suggest you report this to IDF team, as it seems this is not the proper way things should be. There is no reason why IO0 can't be used