Bus_SPI: detect SCT on ESP-IDF 6.1

[ainyan03]

ESP-IDF 6.1 removed SOC_SPI_SCT_SUPPORTED and SOC_SPI_SCT_SUPPORTED_PERIPH from soc_caps.h; the capability is now SPI_LL_PERIPH_HAS_SCT(host) in hal/spi_ll.h. Bus_SPI found neither macro, so the Segmented-Configure-Transfer path was compiled out on ESP32-S3 / C3 / C6 / C2 / H2 with ESP-IDF 6.1:

• DMA transfers over 32 KB fell back to restarting every segment from the CPU and waiting for it in between.
• The SCT-only transfer fixes (AFIFO reset before start, CS setup right after an SCT transfer) were dropped as well.

This PR falls back to hal/spi_ll.h on ESP-IDF 6.1 and later, only when soc_caps.h has no SCT macros. It also uses one LGFX_SPI_SCT_PERIPH(host) for both the compile-time check and the per-host runtime check. Older ESP-IDF keeps using soc_caps.h and does not include the LL header.

Tested:

• The SCT check result per build: on for ESP32-S3 with ESP-IDF 6.1 (off before this PR), 6.0.2 and 5.5; off for ESP32-P4 and ESP32-C5 with 6.1, which have no SCT
• Builds across the Arduino and ESP-IDF versions used by the CI (4.4 to 6.1)
• Hardware, ESP32-S3 with ESP-IDF 6.1, a 150 KB image sent as one DMA transfer (pushImageDMA) and read back from the panel:

	Read-back mismatches	Time until the call returns	Time until the transfer ends
SCT (this PR)	0	0.06 ms	30.8 ms
No SCT (the path used before this PR)	0	24.2 ms	30.8 ms