simd: detect -rt kernels >= 5.4

The 5.4 series of -rt kernels moved from PREEMPT_RT_BASE/PREEMPT_RT_FULL
to PREEMPT_RT, so we have to account for it here. Otherwise users get
scheduling-while-atomic splats.

Reported-by: Erik Schuitema <erik@essd.nl>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff --git a/src/compat/simd/include/linux/simd.h b/src/compat/simd/include/linux/simd.h
index c75c724..3ff8a02 100644
--- a/src/compat/simd/include/linux/simd.h
+++ b/src/compat/simd/include/linux/simd.h
@@ -25,7 +25,7 @@
 
 static inline void simd_get(simd_context_t *ctx)
 {
-	*ctx = !IS_ENABLED(CONFIG_PREEMPT_RT_BASE) && may_use_simd() ? HAVE_FULL_SIMD : HAVE_NO_SIMD;
+	*ctx = !IS_ENABLED(CONFIG_PREEMPT_RT) && !IS_ENABLED(CONFIG_PREEMPT_RT_BASE) && may_use_simd() ? HAVE_FULL_SIMD : HAVE_NO_SIMD;
 }
 
 static inline void simd_put(simd_context_t *ctx)