Release v5.2.6

Release v5.5.1

Release v5.3.4

Release v5.5

refactor(xtensa): Rename specreg.h register macros

This commit renames all registers in xtensa/specreg.h to by adding the
prefix XT_REG_. This is done to avoid naming collisions with similar
variable names. A new register file, viz., xt_specreg.h is created. The
previous names are still available to use but have been deprecated.

Closes espressif#12723
Merges espressif#16040

fix(newlib): add missing __atomic_test_and_set for RISCV chips wo 'a'…

… extension

Before the change described in
https://gcc.gnu.org/pipermail/gcc-patches/2023-September/631393.html it
appeared that inlining built-in GCC function __atomic_test_and_set() was
incorrect. It resulted in a non-atomic write.
After the change now present in GCC, the IDF should include the function
__atomic_test_and_set() to successfully link the final binary.

Closes espressif#15167

Support NVS encryption without flash encryption

Release v5.4.2

Release v5.5-beta1

Start of v6.0 development