fbdev: msm: Fix compilation error for user build

CONFIG_DEGUG_FS is disabled in user build. This
change resolves the compilation errors which
occurred when CONFIG_DEBUG_FS flag is disabled.

Change-Id: I2c5c5121178fc78eec2524ee1088579ceb020adb
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>