sh: Tidy up gzip-based zImage decompression.

This brings the zImage handling in to the current century, in preparation
for handling the other compression types.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 120bd31..9f531ca 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -17,6 +17,7 @@
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_DMA_API_DEBUG
 	select HAVE_PERF_COUNTERS
+	select HAVE_KERNEL_GZIP
 	select RTC_LIB
 	select GENERIC_ATOMIC64
 	help