mtd: maps: Allow MTD_PHYSMAP with MTD_RAM

When the physmap_of_core.c code was merged into physmap-core.c the
ability to use MTD_PHYSMAP_OF with only MTD_RAM selected was lost.
Restore this by adding MTD_RAM to the dependencies of MTD_PHYSMAP.

Fixes: commit 642b1e8d ("mtd: maps: Merge physmap_of.c into physmap-core.c")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/mtd/maps/Kconfig

@@ -10,7 +10,7 @@ config MTD_COMPLEX_MAPPINGS
 
 config MTD_PHYSMAP
 	tristate "Flash device in physical memory map"
-	depends on MTD_CFI || MTD_JEDECPROBE || MTD_ROM || MTD_LPDDR
+	depends on MTD_CFI || MTD_JEDECPROBE || MTD_ROM || MTD_RAM || MTD_LPDDR
 	help
 	  This provides a 'mapping' driver which allows the NOR Flash and
 	  ROM driver code to communicate with chips which are mapped