mtd: physmap: Use *-y instead of *-objs in Makefile

*-objs suffix is reserved rather for (user-space) host programs while
usually *-y suffix is used for kernel drivers (although *-objs works
for that purpose for now).

Let's correct the old usages of *-objs in Makefiles.

Signed-off-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>
Link: https://lore.kernel.org/linux-mtd/[e-mail]

drivers/mtd/maps/Makefile

···
 obj-$(CONFIG_MTD_CK804XROM)	+= ck804xrom.o
 obj-$(CONFIG_MTD_TSUNAMI)	+= tsunami_flash.o
 obj-$(CONFIG_MTD_PXA2XX)	+= pxa2xx-flash.o
-physmap-objs-y			+= physmap-core.o
-physmap-objs-$(CONFIG_MTD_PHYSMAP_BT1_ROM) += physmap-bt1-rom.o
-physmap-objs-$(CONFIG_MTD_PHYSMAP_VERSATILE) += physmap-versatile.o
-physmap-objs-$(CONFIG_MTD_PHYSMAP_GEMINI) += physmap-gemini.o
-physmap-objs-$(CONFIG_MTD_PHYSMAP_IXP4XX) += physmap-ixp4xx.o
-physmap-objs			:= $(physmap-objs-y)
 obj-$(CONFIG_MTD_PHYSMAP)	+= physmap.o
+physmap-y			:= physmap-core.o
+physmap-$(CONFIG_MTD_PHYSMAP_BT1_ROM) += physmap-bt1-rom.o
+physmap-$(CONFIG_MTD_PHYSMAP_VERSATILE) += physmap-versatile.o
+physmap-$(CONFIG_MTD_PHYSMAP_GEMINI) += physmap-gemini.o
+physmap-$(CONFIG_MTD_PHYSMAP_IXP4XX) += physmap-ixp4xx.o
 obj-$(CONFIG_MTD_PISMO)		+= pismo.o
 obj-$(CONFIG_MTD_PCMCIA)	+= pcmciamtd.o
 obj-$(CONFIG_MTD_SA1100)	+= sa1100-flash.o