riscv32: Use medany C model for modules

When CONFIG_CMODEL_MEDLOW is used it ends up generating riscv_hi20_rela
relocations in modules which are not resolved during runtime and
following errors would be seen

[    4.802714] virtio_input: target 00000000c1539090 can not be addressed by the 32-bit offset from PC = 39148b7b
[    4.854800] virtio_input: target 00000000c1539090 can not be addressed by the 32-bit offset from PC = 9774456d
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/Makefile

@@ -16,7 +16,7 @@ ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
 	CC_FLAGS_FTRACE := -fpatchable-function-entry=8
 endif
 
-ifeq ($(CONFIG_64BIT)$(CONFIG_CMODEL_MEDLOW),yy)
+ifeq ($(CONFIG_CMODEL_MEDLOW),y)
 KBUILD_CFLAGS_MODULE += -mcmodel=medany
 endif