prism54: move under intersil vendor directory

Part of reorganising wireless drivers directory and Kconfig.

Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
diff --git a/drivers/net/wireless/intersil/Makefile b/drivers/net/wireless/intersil/Makefile
index aedb713..9a8cbfe 100644
--- a/drivers/net/wireless/intersil/Makefile
+++ b/drivers/net/wireless/intersil/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_HOSTAP)		+= hostap/
 obj-$(CONFIG_HERMES)		+= orinoco/
 obj-$(CONFIG_P54_COMMON)	+= p54/
+obj-$(CONFIG_PRISM54)		+= prism54/