riscv: Kconfig: Fix indentation and add comments

The convention for indentation seems to be a single tab. Help text is
further indented by an additional two whitespaces. Fix the lines that
violate these rules.

While add it, add trailing comments to endmenu statements for better
readability.
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Link: https://lore.kernel.org/r/20220520120232.148310-2-juergh@canonical.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/Kconfig

@@ -343,7 +343,7 @@ config FPU
 
 	  If you don't know what to do here, say Y.
 
-endmenu
+endmenu # "Platform type"
 
 menu "Kernel features"
 
@@ -394,7 +394,7 @@ config CRASH_DUMP
 
 	  For more details see Documentation/admin-guide/kdump/kdump.rst
 
-endmenu
+endmenu # "Kernel features"
 
 menu "Boot options"
 
@@ -430,7 +430,6 @@ config CMDLINE_EXTEND
 	  cases where the provided arguments are insufficient and
 	  you don't want to or cannot modify them.
 
-
 config CMDLINE_FORCE
 	bool "Always use the default kernel command string"
 	help
@@ -522,7 +521,7 @@ config XIP_PHYS_ADDR
 	  be linked for and stored to.  This address is dependent on your
 	  own flash usage.
 
-endmenu
+endmenu # "Boot options"
 
 config BUILTIN_DTB
 	bool
@@ -533,12 +532,12 @@ menu "Power management options"
 
 source "kernel/power/Kconfig"
 
-endmenu
+endmenu # "Power management options"
 
 menu "CPU Power Management"
 
 source "drivers/cpuidle/Kconfig"
 
-endmenu
+endmenu # "CPU Power Management"
 
 source "arch/riscv/kvm/Kconfig"