platform/x86: msi-ec: Fix the build

The msi-ec driver fails to build for me (gcc 7.5):

  CC [M]  drivers/platform/x86/msi-ec.o
drivers/platform/x86/msi-ec.c:72:6: error: initializer element is not constant
    { SM_ECO_NAME,     0xc2 },
      ^~~~~~~~~~~
drivers/platform/x86/msi-ec.c:72:6: note: (near initialization for ‘CONF0.shift_mode.modes[0].name’)
drivers/platform/x86/msi-ec.c:73:6: error: initializer element is not constant
    { SM_COMFORT_NAME, 0xc1 },
      ^~~~~~~~~~~~~~~
drivers/platform/x86/msi-ec.c:73:6: note: (near initialization for ‘CONF0.shift_mode.modes[1].name’)
drivers/platform/x86/msi-ec.c:74:6: error: initializer element is not constant
    { SM_SPORT_NAME,   0xc0 },
      ^~~~~~~~~~~~~
drivers/platform/x86/msi-ec.c:74:6: note: (near initialization for ‘CONF0.shift_mode.modes[2].name’)
(...)

Don't try to be smart, just use defines for the constant strings. The
compiler will recognize it's the same string and will store it only
once in the data section anyway.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Fixes: 392cacf ("platform/x86: Add new msi-ec driver")
Cc: stable@vger.kernel.org
Cc: Nikita Kravets <teackot@gmail.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <markgross@kernel.org>
Link: https://lore.kernel.org/r/20230805101010.54d49e91@endymion.delvare
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Author: jdelvare

drivers/platform/x86/msi-ec.c

@@ -27,15 +27,15 @@
 #include <linux/seq_file.h>
 #include <linux/string.h>
 
-static const char *const SM_ECO_NAME       = "eco";
-static const char *const SM_COMFORT_NAME   = "comfort";
-static const char *const SM_SPORT_NAME     = "sport";
-static const char *const SM_TURBO_NAME     = "turbo";
-
-static const char *const FM_AUTO_NAME     = "auto";
-static const char *const FM_SILENT_NAME   = "silent";
-static const char *const FM_BASIC_NAME    = "basic";
-static const char *const FM_ADVANCED_NAME = "advanced";
+#define SM_ECO_NAME		"eco"
+#define SM_COMFORT_NAME		"comfort"
+#define SM_SPORT_NAME		"sport"
+#define SM_TURBO_NAME		"turbo"
+
+#define FM_AUTO_NAME		"auto"
+#define FM_SILENT_NAME		"silent"
+#define FM_BASIC_NAME		"basic"
+#define FM_ADVANCED_NAME	"advanced"
 
 static const char * const ALLOWED_FW_0[] __initconst = {
 	"14C1EMS1.012",