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

module/icp/algs/edonr/edonr.c

@@ -346,9 +346,11 @@ Q256(size_t bitlen, const uint32_t *data, uint32_t *restrict p)
  * which only goes over it by a hair (1248 bytes on ARM32).
  */
 #include <sys/isa_defs.h>	/* for _ILP32 */
-#ifdef _ILP32   /* We're 32-bit, assume small stack frames */
+#if defined(_ILP32)   /* We're 32-bit, assume small stack frames */
+#if defined(__GNUC__) && !defined(__clang__)
 #pragma GCC diagnostic ignored "-Wframe-larger-than="
 #endif
+#endif
 
 #if defined(__IBMC__) && defined(_AIX) && defined(__64BIT__)
 static inline size_t

module/icp/algs/skein/skein_block.c

@@ -30,7 +30,9 @@
  * the #pragma here to ignore the warning.
  */
 #if defined(_ILP32) || defined(__powerpc)	/* Assume small stack */
+#if defined(__GNUC__) && !defined(__clang__)
 #pragma GCC diagnostic ignored "-Wframe-larger-than="
+#endif
 /*
  * We're running on 32-bit, don't unroll loops to save stack frame space
  *