firmware: qcom: tzmem: don't ask about allocator mode when not enabled

The Qualcomm firmware code shouldn't ask about what memory allocator
mode should be used when the code isn't even enabled.

Get rid of pointless config-time question.

Link: https://lore.kernel.org/all/CAHk-=wg+38EHPKGou1MqXwAAXC30cM8sMgZAGnZ7TcFO4L9J2w@mail.gmail.com/Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/firmware/qcom/Kconfig

@@ -16,6 +16,7 @@ config QCOM_TZMEM
 
 choice
 	prompt "TrustZone interface memory allocator mode"
+	depends on QCOM_TZMEM
 	default QCOM_TZMEM_MODE_GENERIC
 	help
 	  Selects the mode of the memory allocator providing memory buffers of