Fix Clang 15 compilation errors
- Clang 15 doesn't support -fno-ipa-sra anymore. Do a separate check for -fno-ipa-sra support by $KERNEL_CC.
- Don't enable -mgeneral-regs-only for certain module files. Fix #13260
- Scope GCC diagnostic ignored statements to GCC only. Clang doesn't need them to compile the code.
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: szubersk <szuberskidamian@gmail.com>
Closes #13260
Closes #14150