common: fix detection of SYS_MALLOC_F_LEN=0x0

CONFIG_$(SPL_TPL_)SYS_MALLOC_F_LEN is defined as hex. If set to zero
manually, .config contains '0x0' and not '0' as value.

The default value for CONFIG_SPL_SYS_MALLOC_F_LEN should not be set to 0
but to 0x0 if CONFIG_SPL_FRAMEWORK=n to match a manually set value.

Fixes: c0126bd862a0 ("spl: Support bootstage, log, hash and early malloc in TPL")
Fixes: b61694705217 ("SPL: Do not enable SPL_SYS_MALLOC_SIMPLE without SPL_FRAMEWORK by default")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/common/Makefile b/common/Makefile
index c87bb2e..f5c3d90 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -79,7 +79,7 @@
 obj-$(CONFIG_CROS_EC) += cros_ec.o
 obj-y += dlmalloc.o
 ifdef CONFIG_SYS_MALLOC_F
-ifneq ($(CONFIG_$(SPL_TPL_)SYS_MALLOC_F_LEN),0)
+ifneq ($(CONFIG_$(SPL_TPL_)SYS_MALLOC_F_LEN),0x0)
 obj-y += malloc_simple.o
 endif
 endif