efivars: fix warnings when CONFIG_PSTORE=n

drivers/firmware/efivars.c:161: warning: ‘utf16_strlen’ defined but not used
utf16_strlen() is only used inside CONFIG_PSTORE - make this "static inline"
to shut the compiler up [thanks to hpa for the suggestion].

drivers/firmware/efivars.c:602: warning: initialization from incompatible pointer type
Between v1 and v2 of this patch series we decided to make the "part" number
unsigned - but missed fixing the stub version of efi_pstore_write()

Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

drivers/firmware/efivars.c

@@ -157,7 +157,7 @@ utf16_strnlen(efi_char16_t *s, size_t maxlength)
 	return length;
 }
 
-static unsigned long
+static inline unsigned long
 utf16_strlen(efi_char16_t *s)
 {
 	return utf16_strnlen(s, ~0UL);
@@ -580,8 +580,8 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 	return -1;
 }
 
-static u64 efi_pstore_write(enum pstore_type_id type, int part, size_t size,
-			    struct pstore_info *psi)
+static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
+			    size_t size, struct pstore_info *psi)
 {
 	return 0;
 }