libc/baselibc: Fix floating point argument access

When commint "Add va_list pointer compiling error workaround"
was introduced path for FLOAT_USER was not updated as all other
places that use va.

It result in va and va_to_pass used if formating string contains
%f and other like "%f %s %s"
This can result in wrong argument selection.

Signed-off-by: Jerzy Kasenberg <jerzy.kasenberg@codecoup.pl>

libc/baselibc/src/tinyprintf.c

@@ -380,7 +380,7 @@ size_t tfp_format(FILE *putp, const char *fmt, va_list va)
 #if MYNEWT_VAL(FLOAT_USER)
  case 'f':
  p.base = 10;
- d = va_arg(va, double);
+ d = va_arg(va_to_pass, double);
  /* Convert to an int to get the integer part of the number. */
  n = d;
  /* Convert to ascii */