Workaround Uncrustify parsing of "asm"

The following code:

 #ifndef asm
 #define asm __asm
 #endif

causes Uncrustify to stop correcting the rest of the file. This may be
due to parsing the "asm" keyword in the definition.

Work around this by wrapping the idiom in an *INDENT-OFF* comment
wherever it appears.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/include/mbedtls/bn_mul.h b/include/mbedtls/bn_mul.h
index a3fc363..30d445e 100644
--- a/include/mbedtls/bn_mul.h
+++ b/include/mbedtls/bn_mul.h
@@ -86,9 +86,11 @@
 
 #if defined(MBEDTLS_HAVE_ASM)
 
+/* *INDENT-OFF* */
 #ifndef asm
 #define asm __asm
 #endif
+/* *INDENT-ON* */
 
 /* armcc5 --gnu defines __GNUC__ but doesn't support GNU's extended asm */
 #if defined(__GNUC__) && \