[MIPS] Kconfig: Clarify description of CROSSCOMPILE.

	bool "Are you using a crosscompiler"

	help

	  Say Y here if you are compiling the kernel on a different

	  architecture than the one it is intended to run on.

	  architecture than the one it is intended to run on.  This is just a

	  convenience option which will select the appropriate value for

	  the CROSS_COMPILE make variable which otherwise has to be passed on

	  the command line from mips-linux-, mipsel-linux-, mips64-linux- and

	  mips64el-linux- as appropriate for a particular kernel configuration.

	  You will have to pass the value for CROSS_COMPILE manually if the

	  name prefix for your tools is different.

config CMDLINE

	string "Default kernel command string"