Rules.mak: Fix setting arch native bit

fix breakage from 603af30d

Removing the whitespace from findstring for 64 bit architectures has
bad consequences since powerpc would be a match in powerpc64 and sparc
would also be a match in sparc64.
That doesn't make them 64 bits in reality causing general breakage.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

Rules.mak

@@ -141,7 +141,7 @@ UBACKTRACE_DSO := libubacktrace.so.$(ABI_VERSION)
 
 UCLIBC_LDSO_NAME := ld-uClibc
 ARCH_NATIVE_BIT := 32
-ifneq ($(findstring $(TARGET_ARCH),hppa64 ia64 powerpc64 s390x sparc64 x86_64),)
+ifneq ($(findstring  $(TARGET_ARCH) , hppa64 ia64 powerpc64 s390x sparc64 x86_64 ),)
 UCLIBC_LDSO_NAME := ld64-uClibc
 ARCH_NATIVE_BIT := 64
 else