tcg/arm: Simplify use_armv5t_instructions

According to the Arm ARM DDI 0406C, section A1.3, the valid variants
are ARMv5T, ARMv5TE, ARMv5TEJ -- there is no ARMv5 without Thumb.
Therefore simplify the test from preprocessor ifdefs to base
architecture revision.  Retain the "t" in the name to minimize churn.

Reviewed-by: Peter Maydell <[email protected]>
Signed-off-by: Richard Henderson <[email protected]>

Author: rth7680

tcg/arm/tcg-target.h

@@ -28,13 +28,7 @@
 
 extern int arm_arch;
 
-#if defined(__ARM_ARCH_5T__) \
-    || defined(__ARM_ARCH_5TE__) || defined(__ARM_ARCH_5TEJ__)
-# define use_armv5t_instructions 1
-#else
-# define use_armv5t_instructions use_armv6_instructions
-#endif
-
+#define use_armv5t_instructions (__ARM_ARCH >= 5 || arm_arch >= 5)
 #define use_armv6_instructions  (__ARM_ARCH >= 6 || arm_arch >= 6)
 #define use_armv7_instructions  (__ARM_ARCH >= 7 || arm_arch >= 7)