docs: printk-formats: Fix hex printing of signed values

The commit cbacb5ab ("docs: printk-formats: Stop encouraging use of
unnecessary %h[xudi] and %hh[xudi]") obviously missed the point of sign
promotion for the signed values lesser than int. In such case %x prints
not the same as %h[h]x. Restore back those specifiers for the signed hex
cases.

Fixes: cbacb5ab ("docs: printk-formats: Stop encouraging use of unnecessary %h[xudi] and %hh[xudi]")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230703145839.14248-1-andriy.shevchenko@linux.intel.com

Documentation/core-api/printk-formats.rst

@@ -15,9 +15,9 @@ Integer types
 
 	If variable is of Type,		use printk format specifier:
 	------------------------------------------------------------
-		char			%d or %x
+		char			%d or %hhx
 		unsigned char		%u or %x
-		short int		%d or %x
+		short int		%d or %hx
 		unsigned short int	%u or %x
 		int			%d or %x
 		unsigned int		%u or %x
@@ -27,9 +27,9 @@ Integer types
 		unsigned long long	%llu or %llx
 		size_t			%zu or %zx
 		ssize_t			%zd or %zx
-		s8			%d or %x
+		s8			%d or %hhx
 		u8			%u or %x
-		s16			%d or %x
+		s16			%d or %hx
 		u16			%u or %x
 		s32			%d or %x
 		u32			%u or %x