ARMv7 SIMD: Fix clang compatibility (Part 2)

GCC does support UAL syntax (strbeq) if the ".syntax unified" directive
is supplied.  This directive is supported by all versions of GCC and
clang going back to 2003, so it should not create any backward
compatibility issues.

Based on mattsarett/libjpeg-turbo@1264349

Closes flutter#76

simd/jsimd_arm_neon.S

@@ -35,6 +35,7 @@
 .arch armv7a
 .object_arch armv4
 .arm
+.syntax unified
 
 
 #define RESPECT_STRICT_ALIGNMENT 1
@@ -2457,11 +2458,7 @@ asm_function jsimd_h2v1_fancy_upsample_neon
     strb            \TMP, [\BUFFER, #1]!
     cmp             \TMP, #0xff
     /*it eq*/
-#if defined(__clang__)
     strbeq          \ZERO, [\BUFFER, #1]!
-#else
-    streqb          \ZERO, [\BUFFER, #1]!
-#endif
 .endm
 
 .macro put_bits PUT_BUFFER, PUT_BITS, CODE, SIZE