Rules.mak fix typo (qstrup -> qstrip)

Signed-off-by: Austin Foxley <austinf@cetoncorp.com>

Rules.mak

@@ -94,7 +94,7 @@ export ARCH
 # Make certain these contain a final "/", but no "//"s.
 TARGET_SUBARCH:=$(call qstrip,$(shell grep -s '^TARGET_SUBARCH' $(top_builddir)/.config | $(SED) -e 's/^TARGET_SUBARCH=//'))
 TARGET_SUBARCH:=$(call qstrip,$(TARGET_SUBARCH))
-RUNTIME_PREFIX:=$(strip $(subst //,/, $(subst ,/, $(call qstrup,$(RUNTIME_PREFIX)))))
+RUNTIME_PREFIX:=$(strip $(subst //,/, $(subst ,/, $(call qstrip,$(RUNTIME_PREFIX)))))
 DEVEL_PREFIX:=$(strip $(subst //,/, $(subst ,/, $(call qstrip,$(DEVEL_PREFIX)))))
 KERNEL_HEADERS:=$(strip $(subst //,/, $(subst ,/, $(call qstrip,$(KERNEL_HEADERS)))))
 export RUNTIME_PREFIX DEVEL_PREFIX KERNEL_HEADERS