kbuild: initramfs fix dependency checking for compressed target

When using initramfs compression, the data file compression suffix
gets quotes pulled in from Kconfig, e.g., initramfs_data.cpio".gz"
which make does not match a target and causes rebuild.

Fix this by filtering out quotes from the Kconfig string.

Fixes: 35e669e ("initramfs: select builtin initram compression algorithm on KConfig instead of Makefile")
Reviewed-by: Francisco Blas Izquierdo Riera (klondike) <[email protected]>
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

usr/Makefile

@@ -5,7 +5,7 @@
 klibcdirs:;
 PHONY += klibcdirs
 
-suffix_y = $(CONFIG_INITRAMFS_COMPRESSION)
+suffix_y = $(subst $\",,$(CONFIG_INITRAMFS_COMPRESSION))
 AFLAGS_initramfs_data.o += -DINITRAMFS_IMAGE="usr/initramfs_data.cpio$(suffix_y)"
 
 # Generate builtin.o based on initramfs_data.o