media: mxl5xx: Move xpt structures off stack

commit 526f4527 upstream.

When building for LoongArch with clang 18.0.0, the stack usage of
probe() is larger than the allowed 2048 bytes:

  drivers/media/dvb-frontends/mxl5xx.c:1698:12: warning: stack frame size (2368) exceeds limit (2048) in 'probe' [-Wframe-larger-than]
   1698 | static int probe(struct mxl *state, struct mxl5xx_cfg *cfg)
        |            ^
  1 warning generated.

This is the result of the linked LLVM commit, which changes how the
arrays of structures in config_ts() get handled with
CONFIG_INIT_STACK_ZERO and CONFIG_INIT_STACK_PATTERN, which causes the
above warning in combination with inlining, as config_ts() gets inlined
into probe().

This warning can be easily fixed by moving the array of structures off
of the stackvia 'static const', which is a better location for these
variables anyways because they are static data that is only ever read
from, never modified, so allocating the stack space is wasteful.

This drops the stack usage from 2368 bytes to 256 bytes with the same
compiler and configuration.

Link: https://lore.kernel.org/linux-media/20240111-dvb-mxl5xx-move-structs-off-stack-v1-1-ca4230e67c11@kernel.org
Cc: stable@vger.kernel.org
Closes: https://github.com/ClangBuiltLinux/linux/issues/1977
Link: https://github.com/llvm/llvm-project/commit/afe8b93ffdfef5d8879e1894b9d7dda40dee2b8d


Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>